I once heard a beautiful explanation of the meaning of mechila. The popular understanding that everything is forgotten and the relationship between the two parties reverts back to where it was is obviously wrong, especially in cases when lasting damage has already occurred. The true meaning of forgiveness is that when a person harms another human being, a certain negative connection is formed between the offender and the victim which is the cause for all the pain and anger. The offender has shelita, a certain control over the victim. Think about it, when someone offends another person, it only really hurts when the person has some connection to the victim, some kind of bond that is now fueling negative feelings. So mechila is to CUT that negative bond, to say that you have NO control over me anymore and I am not bound by you at all. Now, after that painful process of disconnecting and being able to face the offender without feeling that “feeling” of control, the victim can now determine if this relationship is worth pursuing or not.
This is the true meaning of mechila.