Dear Princess Celestia,
I was wondering way you made me an allicorn and why I'm a princess all of a sudden you know? I was just wondering if you could tell me WHY?
Your faithful student,
Twilight Sparkle
"You can send it to the Princess now Spike"
"Hmm....."
Celestia dipped her quill in the ink and on a fresh piece of paper she began to write.
My most faithful student Twilight,
I knew you would be wondering about all that, the reason is, you created new magic, and you have done many extrodenary things which means that you where ready to become Equestria's newest princess. You understanded friendship more than anypony else could imagine, you have true, magical friendship within you Twilight. That's why.
As twilight read this she started to cry a little bit.