You say she isn't even apologetic. Then you shoul try to understand whether she doesn't care about you or she simply doesn't consider what she did a betrayal at all. In the latter case you simply have different values and you could consider accepting it and forgiving her. In the former case, if you still care for her, consider forgiving her if she'll finally understand she did wrong and apologizes. Otherwise just ditch her, but don't lose faith in the whole humankind, there will always be friends that will never betray you.