People will wrong you in life. It may have been done by accident or the person may have done something to deliberately take advantage of you or harm you.
A willingness to forgive the wrong doer, can help you heal from the emotional harm done by the perpetrator.
However, forgiving is not the same as forgetting.
Once someone has deliberately deceived you or harmed you, do not trust them in the future. To do so would only invite further deception.
Forgiveness may be freely given, but trust and respect must be earned.
Forgivness is also not an automatic pardon. Forgiving someone does not take away the need for punishment or restitution, especially if a crime was committed.
Forgiveness is more about helping yourself heal, then it is about helping the other person.