Rarity had always known. She could always see the little details in everything. It certainly helped when making sure something was clean or that a seam wasn't noticeable. Later in life, she found that it also helped when meeting others. She could see what others couldn't.
That's why when Twilight told her how she felt, she wasn't surprised. She had known since the beginning. It was subtle hints that showed her her true feelings. She could see the secret meaning behind an act of kindness or a smile of happiness when she complimented her.
At first, she denied the signs, thinking she was just misinterpreting them, but soon she found herself warming up to the idea. She would find herself taking extra time on her looks, if that's even possible, and hanging out with Twilight more than the others.
Sure, she wasn't holding her tight on cold nights or walking with her on beach, but the closeness between them kept her happy. They would see each other each day, whether it was for work or just a friendly get-together. She grew closer and closer to her.
She began to grow fond of even a brief exchange with Twilight. She would relish the moments where it was just the two of them, together, doing nothing significant, but memorable all the same. The extreme enjoyment she felt when Twilight looked at her was enough to make all of her troubles melt away. It didn't matter if there was a close deadline, or if somepony was rude to her.
Sometimes, they would come close to starting an official relationship. There would be a special moment, one she thought would be a turning point, and then Twilight would suddenly turn away, nervous, and laugh it off.
Rarity could hear the sentences never spoken and feel the kisses never given. She could imagine how it would play out. She knew how it would turn out because she could see the little things. She could sense the nervousness in the smile and the glimmer of excitement in the eyes and knew exactly what Twilight would do if she could work up the courage.
It was the things Twilight did that made her realize how much she liked her. She would show her more kindness than others. It was always small things, like letting her keep a book after it was due or helping her on some dress. Because she knew Twilight so well she could see how big these things were, even if they seemed small to others.
Twilight was all about schedules and order, so for her to take time to do something stupid or to interrupt the usual order of things, that must mean that she really cared about her. Rarity found herself doing the same thing. She had always loved romance stories, but she began to read other genres.
She read nonfiction and biographies to learn about things for Twilight and her to talk about. She studied magic to impress her with some relatively difficult tricks. She also tried to read Daring Do, but couldn't get herself to finish even one.
She was falling hard for her and she could only assume that Twilight felt the same way. She began to feel more comfortable with Twilight. It took perseverance and strength to keep herself from saying how much she cared for her when they would meet each day. It gradually got harder to even look at Twilight without the urge to kiss her and hold her tight.
But, she could still see the little things. She still saw the twinge of fear in her eyes whenever the two of them got too close. She could still sense the apprehension when Twilight seemed lost in thought. She knew that she was thinking about then, though, because she could see those little things.
She also had those precious moments when both of them were lost in pure happiness just being in each other's company. The bliss of a calm day off, the peaceful serenity of the sunset on a beautiful day or the small wonders in the few moments they had together during their busier days. It was those moments that kept her smiling and kept her from ruining what they had.
Rarity always dreamed of finding her true love. She'd dreamed of finding her knight in shining armor. Within months of her discovery about Twilight, she'd realized that Twilight was true love, the pony she was looking for. She wasn't a knight in shining armor. She was just a librarian who was awkward in social situations and who would freak out at the smallest things.
No, Twilight was not the pony she was expecting to end up with. She wanted somepony who was rich and famous, but she ended up getting somepony who loved her and would always be there for her. Twilight was far better than somepony like Blueblood. She was her best friend, the one she turned to when she was in trouble. What more could she ask for?
Her flaws made her unique and Rarity knew from experience that if you didn't have flaws then weren't showing the real you. Twilight was far from perfect, but she was the best kind of pony. She was smart, cute, funny and she made Rarity feel happy. She had a heart as pure as gold and seemed to make a connection with every pony she met.
Rarity had been sure of her feelings for some time and Twilight had loved her since the beginning. She had seen all the little things and knew that they were meant to be together. She could see that nervous smile and that glimmer of excitement in her eyes. She could see a future of love, of compassion within that one expression. So, when Twilight asked her to be her special somepony, she knew exactly what to say.
It was a simple word, but it spoke more than a million. It held the joy of one thousand lifetimes. It was an answer that came from her heart without thought.
"Yes."