Dear {Recipient}
The unlawful taking of {stolen item} from {victim} has created an uncomfortable situation for which I am very sorry.
It was an inexcusable lapse in judgment and moral behavior on my part. While it was an embarrassing experience, it is an experience I intend to learn and grow from.
I understand that stealing is wrong and what happened on {MM/DD/YYYY} at {location} has taught me that the consequences are not worth the unlawful gain.
Again, I am very sorry for my misbehavior and if {victim} have anything further to discuss on the matter, please feel free to contact me at {email/website/etc…}.
Sincerely,
{Offending Party}