Deuteronomy 21:11-14

And suppose you see among the captives a beautiful woman, and you are attracted to her and want to marry her. If this happens, you may take her to your home, where she must shave her head, cut her nails, and change the clothes she was wearing when she was captured. She will stay in your home, but let her mourn for her father and mother for a full month. Then you may marry her, and you will be her husband and she will be your wife. But if you marry her and she does not please you, you must let her go free. You may not sell her or treat her as a slave, for you have humiliated her.