If her husband hears about the promise and lets her keep her promise, then she must do exactly what she promised. She must give everything she promised.
But if her husband hears about the promise and refuses to let her keep the promise, then she does not have to do what she promised. It does not matter what she promised, her husband can break the promise. If her husband breaks the promise, then the Lord will forgive her.
But if her father hears about the promise and does not agree, then she is free from her promise. She does not have to do the thing she promised. Her father stopped her, so the Lord will forgive her.