he, it, etc. is not as black as he, it, etc. is painted
be (not) as black as (someone or something) is painted
To be as bad or unpleasant as someone or something is rumored to be. This phrase is often used in the negative to convey the opposite. That class is as black as it is painted—I've never had so much homework in my life! Mr. Stewart may yell a lot, but he's not as black as he is painted—he's actually helped me carry my groceries many times.