A girl talked with her fiancé (a friend of her brothers) on the basis of marriage, but he betrayed her and her family, and she now regrets it and asks if what he did was an injustice.

Praise be to Allah, and peace and blessings be upon the Messenger of Allah. Allah Almighty commands the fulfillment of covenants, and when a Muslim makes a covenant with his brother on something, he must fulfill it. Breach of covenant is religiously prohibited and is one of the traits of the hypocrites. Marriage, if agreed upon, must be honored by both parties, and it is not permissible for anyone to corrupt it. However, one of the parties might discover new matters that drive them to dissolve the engagement before the contract, and this is easier than divorce after the contract, but it remains a breach of covenant if it is without a legitimate justification. One cannot judge a person as unjust or treacherous without knowing the true matter of the situation.