Back to City
BaiYing gave him the pure divine energy which make him turn back to its original form, on the condition that XiaoWu would continue his duty as the protector of the forest, just like ErWang, the creature would not be able to leave this forest no matter what, or else BaiYing would come back here and take all of the creature's divine energy, even in a distance the boy able to withdraw his energy and makes XiaoWu lost all of his divine energy.
XiaoWu fell grateful because BaiYing didn't kill him, he regrets all of his actions will never forget how lucky he's now, as a pet being of the Goddess, he made a huge mistake for falling into the mortal's lust, and his desire to repent made a bond of an oath that would destroy his body if he steps out of the XiaoWu's forest.