知人知面不知心

Explanation: Old saying. Means easy to know a person, but to understand a person's heart is very difficult. 　　Usage: Complex sentence; as object clause; that is difficult to know people 　　Source: Qing Cao Xueqin's "Dream of Red Mansions" XI Xifeng children back to his feet placed late on purpose, to see him gone, and my heart Ancun Road, this is the 'Clothes make the man' it. There are people like animals? " 　　Examples: Xifeng child put his feet late on purpose, to see him gone, and my heart Ancun said: "This is the '~' it. There are people like animals?" (Qing Cao Xueqin's "Dream of Red Mansions" X a return)