As Zhang Yi had promised he told her everything that had happened and said she is his master, after telling him how he had supreme understanding in 10 laws and that he used the laws of time to turn back time throughout the universe she partially believed him.
Even so, Wu Qinxin was surprised to learn that Zhang Yi had supreme understanding in 10 different laws and besides being in the realm of mortal tribulation he was still in the eighth realm of body refinement and especially mental energy.
After seeing that it was true and telling that she had a world of mental energy, Wu Qinxin really believed that Zhang Yi was her disciple because that was a technique that only her sect had and she as an elder was allowed to pass on this technique to few people.