Does the father of the girl’s oath of divorce, which he made to the girl’s mother regarding not marrying his daughter to me, take effect, and is expiation obligatory upon him, and what is the ruling on his forcing his daughter to marry someone other than me?

A man's statement: "By divorce, she will not take it," is considered a conditional divorce. The majority of scholars hold that it takes effect upon the fulfillment of the condition. However, another view, which is the more preponderant one, is that the matter depends on the speaker's intention: if he intended divorce, then it occurs; but if he merely intended to prevent something, then this is an oath that requires expiation for breaking an oath (kaffarat yamin (definition)) if he violates it. The questioner is advised to perform Istikhara (prayer for guidance), be patient, and accept God's decree if the girl's father refuses. Similarly, the girl should fear God and accept a suitor who possesses religious commitment and good character.