Repentance means to turn away from one's actions. Whatever was wrong, we have turned from it and are now doing something new.
True and full forgiveness is based on repentance. It is often you see that people seek forgiveness but do not repent.
Often the church muddles everything by suggesting that we must forgive those who will not repent. You see there is a certain sort of peace or lack of anger we should have with the unrepentant.
Holding a grudge or stewing in anger is not Christian. We are to love our enemies. But it is very different to forgive the unrepentant or pretend nothing happened or is still happening.
And that is the great flaw in much of the teaching of the church of today. The idea that forgiveness does not need repentance.
We often like to simplify things in theology. We turn words which are not synonyms into synonyms. For instance, forgiveness equals forgetting to the church. It does most certainly not.
Another instance of this is repentance means acting sorry or claiming to be sorry. It most certainly does not.
You see the terms are related but repentance is being genuinely sorry, not saying the words. Often we cannot judge things immediately. We must wait and see but often repentance is faked and the church refuses to call a spade a spade.