A proverb meaning appearances can be deceptive; you shouldn't judge someone's nature or ability by their looks alone.
初めは地味な印象だったが、仕事ぶりを見て驚いた。人は見かけによらぬものだ。
At first they seemed plain, but I was surprised by their work. People can't be judged by appearances.
彼はおとなしく見えるが、実はリーダーシップがある。人は見かけによらぬものだね。
He seems quiet, but actually has leadership. You really can't judge by appearances.
求人票だけで判断せず、面接で直接会ってみよう。人は見かけによらぬものだ。
Don't judge only by the job posting; meet in person at the interview. Appearances can be deceiving.