People
As blushing will sometimes make a whore pass for a virtuous woman, so modesty may make a fool seem a man of sense.
— Jonathan Swift

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The saying argues that outward signals can mislead people about character or intelligence. It links blushing with modesty and uses a morally loaded comparison to cast doubt on both. Its barbed point is that appearing reserved or innocent does not necessarily establish the quality being inferred.
Context reviewed