This e-mail is for when you've been hurt by someone and want to finally forgive them.
Do you know how much you hurt me? I think now you do. I know that you've been beating yourself up over what happened, and I don't want you to suffer anymore. So...I forgive you. I know you didn't mean to hurt me, and I know that if you had it to do over again, you wouldn't <describe hurtful circumstance>. So because I know you're a good person, and because I care about you, I'm going to let bygones be bygones. I hope we're still friends. Let's put this behind us, and make sure that nothing like this ever happens again, OK?