Dear Twilight Sparkle,
You have been my most faithful student for many years. You have learned what friendship is all about. That is something special and important. You earned your crown, and I couldn't be prouder of your success. I trust all six of you with the Elements of Harmony. You have have the experience I could never have.
There are some things that are better left unspoken. I used to think my past was one of them. It was not a sunny past. My life was threatened more than a hundred countable times. Who wouldn't want to kill the future princess, wanting to get to the throne? If only there were ponies like you six back then, maybe I could have prevented the prophecy of Luna. Of course, that coild mean she would have never been born. I love my sister, honest, with all my heart. Most people think it was my fault she became evil. And it was. I didn't see the signs of her awakening. I had forgotten my promise to always try to find some way to protect her from turning into Nightmare Moon. I have repeated many mistakes that I hope you never encounter.