If she does re-learn the art of trusting, it will never be the same. She shares some of her observations. If a woman's being betrayed, her reaction to her man having done that depends on the effects of the betrayal. If the betrayal breaks a fundamental trust, every effort should be made to regain the trust. If that is not possible, the woman should consider separation.
Counseling can be very helpful if both partners participate to rebuild trust.
Dumping signals the end of a relationship through the exit of one of the partners. Betrayal applies to a state of broken fidelity within the relationship. Often a man breaks off a relationship out of interest in another woman. Betrayal occurs when the defenses are down, but the trust and the relationship can remain. This most likely means the death of the relationship because the woman will not want the man back if he comes around later.