Forgiveness is a very tricky issue. But in the end it really is a matter of freeing the owner of the obligation to be angry. Anger is an emotion that takes up a lot of energy. The subject of your anger rarely realizes or even cares that you are angry at her or do not wish to forgive her for her transgressions. So she moves on in her daily routine without a thought or a care to what you are experiencing. Does she expend any energy towards you? NO. Does she care how you feel? No. Does how you feel or does your anger towards her bother her in any way or take anything away from her? No not really or she would do something to correct the situation. So who does it really affect? You. The only one the entire issue affects is you. The anger and resentment that you harbor only affects you. It takes up your time, your attention and your energy. So if you choose to forgive this unfortunate uncaring person who will it help and who will it affect? The only person it will affect is you. You will no longer think about her, and you will no longer relive the pain of her actions towards you. If you choose to forgive her foolishness, her stupidity and her carelessness towards you then you release yourself from the prison of pain and anger that the situation created and you get to move on with your life. That is what happens with forgiveness.
The next step is this. If she is NOT a good choice as a friend for you, then obviously you have the choice to no longer be friends with her and not keep her in your Quality World. You can place her outside the scope of your inner circle and no longer think about her or deal with her. If at some time in her life she wakes up and misses the connection with you, and then chooses to ask mechila from you, you can choose to tell her that you have already forgiven her a long time ago because it wasn’t worth it for you to be angry at her and you had chosen to move on. You can then decide whether you will allow her back into your life or continue on without her.
Does that make sense to you? Is that something you could consider?