don't believe everything you hear; hearsay paradise, reality hell
Proverb warning that things heard about often sound wonderful, but the reality can be harshly disappointing.
The proverb 'hearing it's paradise, seeing it's hell' means that something may sound wonderful when you only hear about it, but when you actually see it, it's disappointing.
A Japanese proverb contrasting the bliss of hearsay (極楽, paradise) with the harshness of reality (地獄, hell). The exact origin is uncertain, but it reflects a common folk wisdom about the gap between expectation and reality.