How did Senior Mrs. Jing save him? It happened about a dozen years ago. Back then, he went out of control during cultivation and he needed a woman to help him out. Senior Mrs. Jing appeared coincidentally and he raped her.
After the evil cultivator raped Senior Mrs. Jing, he calmed down and felt a little guilty. He owed her a favor and she could ask him to do anything in the future. Even if she needed him to kill someone, he would do whatever he could do.
In addition to the day when the evil cultivator raped Senior Mrs. Jing, Senior Mrs. Jing was forced to take care of him for a few days. During these days, they had sex with each other as well.
At the beginning, Senior Mrs. Jing refused, but she gradually gave in because the evil cultivator was skilled at sex. She was forced to have sex with him during the first two days, but she changed her attitude afterwards.