Xin Plains Master wasn't willing to let Yin Zheng divorce Yuan Ying. However, Yin Zheng uses the jade pendant he finds when he saves Yin Song and exchanges it for Yuan Ying's freedom. Xin Plains Master never expects Yin Zheng to act like that. In the end, he agrees with it. However, he wants Yin Zheng to convince Jin Plains Master himself. After all, Jin Plains Master was the one who suggested the marriage. (Source: Viu)