Dear [Mr. Love] <----- Put who ever you giving this letter to
I sincerely apologize for trying to steal.
I deeply regret all the trouble I have caused to [store/place name] as a result of my action. I feel remorseful in taking up your time with this ruckus I created. The only good of this situation is that I was caught; I feel strangely relieved. I can't express why I stole, and I can't say I didn't know it was wrong. I can only say it was a moment of poor decision. I guess has a lot to do with youth and stupidity of being in a group however, this is one I don't plan on falling prey to again.
I am deeply ashamed of the stupidity of my action, and can only promised to never repeat them.
It is presumptuous of me, but please accept my apologizes
Yours Sincerely,
[Victim of peer pressure] <---- insert your name
And for the Anon who said just give us a letter to get away with it, its cliche but "Crime doesn't pay" letters are only effective the first time, after that it doesn't matter now sincere you look and may by then how sincere you are. They wont believe you
Good Luck