Rarity truly did love her newborn foal Sweetie Belle. So named after her sweet sounding voice and beautiful coat. However it was her equal and almost greater love for her future career; which was to run her own fashion boutique someday in Canterlot that drove her to this decision. Ever since she brought her newborn filly home from the hospital Rarity was the most caring mother any foal could hope for. Sweetie Belle's cry was a rare thing to hear as Rarity was always on top of her daughter's needs as she nursed her, kept her diaper changed, brushed her beautiful mane, bathed her shiny lavender coat, held her for hours on end during her first fever, dressed her in the most adorable little filly dresses, and rocked her to sleep every night. So far it seemed the only downside to the whole situation was that Rarity's coltfriend simply walked out of the picture as soon as her stomach started to show. It was at that point the pregnancy became real to him as well and it all seemed to hit him like a train at once; so he just decided to not come back the next day or any day after that.
Her parents had decided to wait a few weeks to let their daughter and granddaughter settle in; before having the serious discussion about what it meant now that Rarity was a single mother to a newborn foal. Upon entering the brightly decorated nursery they found Rarity tending to Sweetie Belle's runny nose as she just had a recent bout of sneezing. Sweetie Belle giggled as the soft fluffy cloth tickled her nose.
"Rarity." Both of her parents said in unison.
"Yes mommy and daddy dearest?" She replied.
"We feel its time now that we discuss your situation with Sweetie Belle."
"Oh wonderful! I've been meaning to bring a few things up as well."
"So you see Rarity. Even though you have finished high school. We have decided that we can't let you leave Sweetie Belle here with us as you go off to fashion school. You need to stay here in Ponyville and find a job so you can work on learning responsibility."
"But... But... Mom, Dad! I've worked so hard with her up until now. Haven't I proved myself?
"Well yes Rarity, but you see having a foal is a lifelong commitment that you can't just shove onto somepony else after a while. You are going to have work and care for your daughter for at least the next few years until you can save up enough to pay for fashion school and foalsitters yourself."
"No that's not fair! So not fair! If I put off fashion school that long I'll never make it into Canterlot! Mom why can't you raise her? You are retired for Celestia's sake!"
"Now Rarity. I enjoy spending time with Sweetie Belle and have no problem watching her from time to time, but our family is known for behaving with the highest standards which means raising your foal yourself. Once other ponies finally find out you have a foal we can't have our family's name shamed due to your actions."
"But mother! This is my dream we are talking about. I won't just give it up that easily just because... Wait! I know the solution! Why can't we just all agree she is my new baby sister that you had and we can raise Sweetie Belle as such. No pony will ever know."
"Rarity not only are we appalled you would lie to your daughter about her life, but that idea would be impossible. You come from a long line of the purest of white unicorns, and your filly has a lavender coat. No one would believe it for one moment. Our decision is final on this matter. Once this weekend is over you must begin searching for a job in town. Now we are off for dinner and will be back by sunset. You need to think heavily about your life ahead of you."
This whole time Sweetie Belle was just sitting up in her crib as she held on to her blanket Rarity had knitted her. She couldn't understand most words yet and was confused why the only ponies she knew were talking loudly back and forth and not paying her any attention. The little filly wasn't used to being ignored and started becoming upset. She then picked up her rattle with her mouth and shook it vigorously to try and gain Rarity's attention. After wiping the few tears she wasn't able to hold back Rarity turned around to the crib to see what all the racket was about. Sweetie Belle was just sitting there looking up at Rarity as she shook her head back and forth; she reached up to Rarity with her front legs, and stared at her with big sad eyes. Rarity then used her magic to wrap Sweetie Belle in her blanket and levitate her daughter over to her embrace. As she stood up on her hind legs to hold her foal Rarity whispered to her:
"There there my precious little darling. This isn't your fault as you have done nothing wrong."
Sweetie Belle dropped her rattle as she made a large toothless and gummy smile. She loved nothing more than the warm loving attention of her mother. Rarity then walked over to the rocking chair and began to rock her foal gently as she started to think of any way she could still keep her dream alive without disappointing her parents. It wasn't long before Sweetie Belle drifted off into a quiet nap as she let out a cute yawn, and turned to snuggle up closer to her mothers chest. Rarity looked down and almost wanted to cry again. She brought this fragile pony into this world and it became her job to protect it, and now she was contemplating how to pass her off even though it would be temporary. Not even a few minutes into her sleep Sweetie bell started to squirm around in her blanket as she cried out a few small whimpers. This was her first nightmare and Rarity feared she might have caused it by yelling at her parents in front of Sweetie Belle.
Rarity used her magic to gently levitate Sweetie Belle back into crib and walked over to lay down beside it in case her filly woke up crying. Rarity herself then had her own nightmare as she fell into her own deep sleep. While Sweetie Belle's just about being ignored Rarity's much darker and frightening for her. It boiled down to the world around her crumbling apart as she was chained to her daughters crib; the nursery was now her prison and personal hell. No matter what Rarity did for or brought to her daughter she just kept crying and demanding more attention. Rarity was only able to endure so much stress before she woke up exhausted in a cold sweat. It was clear to her now. She HAD to get her parents to accept her daughter as theirs, but her coat was still that troublesome lavender instead of white.
Rarity remembered from reading her books on fashion design that bleach can be used to lighten or completely remove colors and stains from fabrics. She then formulated a sinister plot in her mind. Rarity would just simply scrub her problem away. She was sure diluting the bleach with water would make it safe enough to leave no lasting harm to her daughter. It was in this moment Rarity went from being kind, generous, and caring. To being a self absorbed, selfish, drama queen. Upon glancing at the clock Rarity knew she still had plenty of time before her parents would return from dinner. She then rushed off into the kitchen and rummaged around for a bottle of bleach. She found a brand new bottle underneath the sink and poured some of it out to refill it with water making it not as harmful. After gathering some cloths Rarity returned to Sweetie Belle's nursery. She leaned over the crib to see the unaware foal contently snoring as her first nightmare had ended, but her second one was about to begin. Using her magic Rarity dipped a cloth in the diluted bleach solution and began to scrub an area on Sweetie Belle's stomach to see if her evil plan would work. Sure enough it did and the beautiful shade of lavender washed away to a blank white. Sweetie Belle instantly woke up due to the burning sensation caused by the bleach. She started to cry loudly and tried to flail around but Rarity held her tight with magic, and shouted to her:
"Shut up and hold still! The quicker I finish the sooner my only obstacle standing in my way will be taken down."
After a while about an hour or so longer. Save for her mane and tail Sweetie Belle was finally all white with not a speck of lavender left on her coat. Rarity admired her work as Sweetie Bell was still crying in pain and not a moment later her parents returned.
"Rarity whats wrong!? Why is Sweetie Belle crying so loudly!?"
Rarity turned and help up Sweetie Belle to her parents:
"Look at her mother and father. Look at my solution. Now she can be yours, and everypony will believe it!"
All her parents could do was look on in horror at the hurting foal, and the half empty bottle of bleach sitting next to the crib. They exclaimed:
"Rarity! What in Celestia did you do to your daughter!?"