all that glitters is not gold

God hates a coward; nothing ventured, nothing gained; no pain, no gain

(dated) to see stars after receiving a physical blow / (by extension) to be unable to see the finer details of a complex situation; (particularly) to fall for (a deception), to be taken in, to be totally hoodwinked

honey catches more flies than vinegar; you can catch more flies with honey than with vinegar

there's no smoke without fire

(idiomatic) it's nothing to write home about

contraction of ne + est (third-person singular indicative present form of être)

Alternative form of qui ne risque rien n'a rien

a rolling stone gathers no moss

don't try to teach grandma how to suck eggs