From Zhuangzi Fisherman. True, sincere, impure and sincere, unmoved, crying so strongly, although sad; Strong anger, though strict; Laugh at each other. You can't impress others without sincerity. There's a saying in China that "when the heart really arrives, the stone opens", so you can pay attention to it. This sentence warns people to be sincere and not hypocritical. If the surface is a set, the heart is a set, and the sun is not obedient, it will eventually reveal the clues. As Zhuangzi said in the second half of this sentence, whether it is "crying", "anger" or "kissing", it should not be affected. It should be sincere and heartfelt, so as to impress people.