Adam Clarke on Deuteronomy 21:11

And seest - a beautiful woman - No forcible possession was allowed even in this case, when the woman was taken in war, and was, by the general consent of ancient nations, adjudged as a part of the spoils. The person to whose lot or share such a woman as is here described fell, might, if he chose, have her for a wife on certain conditions; but he was not permitted to use her under any inferior character.