What is the religious ruling on a girl who promised marriage to a man, then married another without informing him, while blaming the first man?

The engagement is a promise of marriage, which it is desirable to fulfill, and it is permissible to break it off for a [valid] reason. However, it is forbidden for a woman to break off an engagement for the sake of another suitor. If the other suitor proposes to the girl while knowing of her engagement, he has committed a forbidden act, but his marriage [to her] is valid. The questioner should not regret what has passed, for perhaps it is better for him. And the suitor is a stranger to the fiancée.