expression
don't trust strangers; always assume the worst of people
A cynical proverb advising extreme caution when dealing with unfamiliar people; literally 'When you see a person, think they are a thief.' Used to warn against being too trusting.
人を見たら泥棒と思えというが、あまり疑いすぎるのもよくない。
They say 'don't trust strangers,' but being too suspicious isn't good either.
This proverb expresses the opposite sentiment: that the world is not full of heartless people and one can find kindness. 人を見たら泥棒と思え is much more cynical.
A traditional Japanese proverb. The exact origin is uncertain, but it reflects a common cautionary attitude toward strangers.