不怕一万，就怕万一
bù​pà​yī​wàn​jiù​pà​wàn​yī

better safe than sorry

不怕一万，就怕万一 不怕一萬，就怕萬一 bù​pà​yī​wàn​jiù​pà​wàn​yī
better safe than sorry
It is better to be safe than sorry; to be prepared for the unlikely event that something goes wrong. Literally "not afraid of the ten thousand normal cases, but afraid of the one-in-ten-thousand chance."