The most successful liar is one who believes everything he deceives and becomes trapped in it, unable to extricate himself. The same is true for Qin Shuang.
If he thought he had deceived himself and others, then it was true. Everyone thought Qin Shuang was a normal person, until many years later Ji Xiuyuan suddenly said, I know you have bipolar disorder. I have always known that you don't have to hide from me. With me here, you can feel at ease. Only then did Qin Shuang realize that even if he had been deceived, he could not deceive the person in front of him who knew him best, Ji Xiuyuan. Suddenly looking back, the man was in the dim light.