What is the ruling on a father swearing an oath of divorce regarding his daughter, that she not marry her paternal cousin whom she desires, and what are the consequences should she marry him?

If a father believes that marrying his daughter to her cousin is better, then he should marry her off, because breaking an oath may sometimes be better. The Prophet, peace and blessings be upon him, said: "If one of you takes an oath and then sees something better than it, let him expiate his oath and do that which is better." As for his oath by divorce, if he proceeds with the marriage, his wife will be divorced from him according to the majority of scholars. He may take her back if he has not divorced her twice before; otherwise, she becomes irrevocably divorced from him according to the first opinion. In either case, he must offer an expiation for an oath. It is advisable to refer the matter to a recognized fatwa authority or the Sharia courts.