we may know a man's exterior but not his heart.; it is impossible to judge a man's heart from his face.; one may know a person for a long time without understanding his true nature.; you know a man or you recognize him when you see him, but you don't know what he is at heart.; you may know a person's face, but not his heart.
Related Translations:
知心理: cognitive psychologypsychology of programming
知: Ⅰ动词1.(知道) know; realize; be aware of 短语和例子强不知以为知 pretend to know what one doesn't know; 无所不知 know everything; omniscient; 知其然并力求知其所以然 know the how and endeavour to know the why; 若要人不知; 除非己