Is it permissible to marry a girl whose guardian has rejected her without reason, knowing that both the young man and the girl have sworn not to marry anyone else, and there is no guardian who can approve?

Among the conditions for the validity of marriage is the permission of the guardian. It is not permissible for her guardian to marry her to someone she does not approve of, nor is it permissible to marry a girl without the permission of her guardian. You both owe an expiation for breaking an oath, which is feeding ten needy people, or clothing them, or emancipating a slave. Whoever cannot find [these means] should fast three days. It is forbidden to propose to a Muslim woman already engaged to another Muslim man, subject to certain specific conditions.