Dear [Name],
I am writing to apologize for the unjustified torment I caused you. I understand that my actions were hurtful and wrong, and I regret them deeply.
I take full responsibility for my actions and want to make it clear that I am truly sorry for what I have done. I realize that my behavior was unacceptable and I should have known better. I was wrong to have treated you in such a way and I want to apologize for the pain and suffering I have caused.
I understand that my actions have caused you a great deal of distress and I am truly sorry for that. I want you to know that I am committed to changing my behavior and making sure that I never hurt you in such a way again. I will strive to be a better person and to treat others with respect and kindness.
I am sorry for the hurt that I have caused you and I am willing to do whatever I can to help you through this process.
Once again, I am deeply sorry for my actions and I hope that you can find it in your heart to forgive me.
Sincerely,
[Your Name]