Deuteronomy 21:10-14

MLV(i) 10 When you go forth to battle against your enemies and Jehovah your God delivers them into your hands and you carry them away captive, 11 and see among the captives a beautiful woman and you have a desire for her and would take her to you as a wife, 12 then you will bring her home to your house. And she will shave her head and pare her nails, 13 and she will put the garments of her captivity from her and will remain in your house and weep for her father and her mother a full month. And after that you will go in to her and be her husband and she will be your wife.
14 And it will be, if you have no delight in her, then you will let her go where she will, but you will not sell her at all for money. You will not deal with her harshly, because you have humbled her.