This proverb is: once bitten, twice shy.

This sentence has an allusion, from Strange Tales from a Lonely Studio. There is a family at the foot of the mountain. This family has two daughters. The eldest daughter's name is Taihō and the youngest daughter's name is Xiaofeng. These two girls are as beautiful as flowers and pure as jade. One day, two sisters were sleeping on the grass, and a snake bit Xiaofeng. Later, after treatment, Xiaofeng developed the habit of being afraid of snakes and saw something similar.