"Piękno otwiera wszelkie zamknięte dzrwi."
"Nie możesz oceniać książki na podstawie jej okładki"
The first proverb means that when a person is beautiful, everything is easier in his or her life. It is easier to make a career, to find a good job, to have a lot of friends. Beauty is important in life and without it, it's more difficult to achieve success.
The second proverb is the opposite to the first one. It means that you can't judge a person when you only look at his or her physical appearance. When someone is beautiful it doesn't mean that he or she is also smart, intelligent and good. You can't say that until you know the person better.