what is its proverb in English [duplicate]
How about Trust, but verify? From Wikipedia:
Trust, but verify is a rhyming Russian proverb. The phrase became internationally known in English when used by President Ronald Reagan on several occasions in the context of nuclear disarmament discussions with the Soviet Union.
It means don't "take at face value," which is another idiom expressing the idea that one shouldn't blindly accept what others say without looking into it first.