You can't judge a book by its cover

tʃaɪniːzle̞tə tä tʃaɪniːzle̞tə te̞ dʒapəniːzle̞tə tʃaɪniːzle̞tə tʃaɪniːzle̞tə sɯᵝ ɽɯᵝ nä ɛm aɪ tiː eɪ ɛm iː diː iː eɪtʃ eɪ ɛn diː eɪ ɛn ɛs juː ɑː juː ɛn eɪ

In Japanese 見た目で判断するな (Mitame de handan suru na)

This proverb is used in Japanese culture to advise against judging based on appearances.