I don’t mean that we as humans can forgive other people’s sins - we cannot - only God can forgive sins - but, we can not let anger, and bitterness grow up within our own hearts for the wrongs done to us. Our telling someone we forgive them, doesn’t resolve their issues with God - they must all seek His forgiveness for sin - It just means that we don’t hold any hard feelings toward the person who wronged us - not that we can absolve their sins.
In more specific terms, we refrain from cursing the person and wish that somehow, he might cede his life to God so as to become a vessel of blessings rather than curses.
It is really weird how so many avowed Christians are dogs in the manger when you put them to a test.