Deuteronomy 21:11-14

21:11 if you should see among them an attractive woman whom you wish to take as a wife, 21:12 you may bring her back to your house. She must shave her head, trim her nails, 21:13 discard the clothing she was wearing when captured, and stay in your house, lamenting for her father and mother for a full month. After that you may have sexual relations with her and become her husband and she your wife. 21:14 If you are not pleased with her, then you must let her go where she pleases. You cannot in any case sell her; you must not take advantage of her, since you have already humiliated her.