There are several types of phobias, and the reason Xiao Qian uses this method to treat Zheng Xu is because she firmly believes that his phobia is triggered by psychological factors rather than heredity and mental quality.
Zheng Xu is neither cowardly nor highly introverted; he's quite responsible. In Northeastern slang, he's a real man. Phobias should not appear in such a person.
So he must have experienced something in a particular year that stimulated him, but he doesn't know it or has chosen to selectively forget it, causing fear in his subconscious.
The only way to deal with such a phobia is to find the person who stimulated him, have that person apologize to Zheng Xu face to face, and then Xiao Qian can guide him to a solution.
But even with such a simple mental illness, Xiao Qian, in her past life, spent half a lifetime trying to solve it unsuccessfully. So she's determined to solve it in this lifetime.
