Dear, Sweetie Belle
Hello, Princess. It's me, Adam. I bet you were surprised to know that I'm writing you a letter. Well, I figured I write it to you to say thanks.
Sweetie Belle, you're the best younger sister to Rarity and sister-in law to Spike. You've been the best member of the Cutie Mark Crusaders and a good friend of Scootaloo and Apple Bloom. When you received your cutie mark, you inspired everypony around you, and even inspired Rarity, Spike & Me too. I'm proud of you, Sweetie Belle. You've been like the best daughter to me and you're the best earth Pony I ever met.
Take care of yourself.
From,
Adam
Sweetie Belle tearfully smiled at the letter that Adam wrote. "Thanks, Adam. You're the best too." Said Sweetie Belle.