If he selects her for his son, he must deal with her as with a daughter.
In context
7If a man sells his daughter as a servant, she is not to go free as male servants do. 8If she is displeasing to her master, who chose her for himself, he must let her be redeemed. He has no right to sell her to foreigners, since he has broken faith with her. 9If he selects her for his son, he must deal with her as with a daughter. 10If he takes another wife, he must not reduce the food, clothing, and marital rights of the first. 11If he does not provide her these three things, she may go free, without any payment.
