expression, ichidan verb
reveal one's limitations; show one's true level; be seen for what it really is
Often used with a negative connotation, implying that someone or something is not as good as expected. The expression is typically used when a person's or thing's true (often low) ability or quality becomes apparent.
彼の実力は、難しい問題を出せば程度が知れる。
His true ability will be revealed if you give him a difficult problem.
The quality of that restaurant's food becomes apparent once you try it.