He wishes to make her his wife.

Or perhaps he has sworn some oath, as I know that he has sworn that he will not murder you--which he might have done a score of times while you have lain a prisoner in his power.

Why, once when you were senseless he came and stood over you, a dagger in his hand, and reasoned out the case with me.
I said, 'Why do you not kill him ?' knowing that thus I could best help to save your life.

He answered, 'Because I will not take my wife with her lover's blood upon my hands, unless I slay him in fair fight.

I swore it yonder in London.