Handsome is as handsome does. You should not be misled by appearances. It is more important to treat people well than to be good-looking.; Just because you are good-looking does not mean you are a good person.
Jill: I'd like to get to know George better.
Jill: He's so handsome.
Jane: Handsome is as handsome does. He's a very rude and unpleasant person.