Zishu naturally had no genuine intention of surrendering. He said those things merely to sow suspicion between Bai Mengjin and the Immortal Alliance, buying himself an opportunity to slip away.
As for why Bai Mengjin so readily admitted to it, it was because she had perceived Cen Muliang's distrust through the incident of Zhou Lingzhu's assassination attempt against her.
Having been master and disciple for decades in her past life, she knew Cen Muliang's temperament well. The more she denied it, the more suspicious Cen Muliang would become. Rather than that, it was better to do the exact opposite and openly acknowledge her ambition.
Chapter 464