Once bitten, twice shy 英文諺語
Once bitten, twice shy 一朝被蛇咬，十年怕草繩
When something or someone has hurt you once, you tend to avoid that thing or person; it means when you have had an unpleasant experience you are much more careful to avoid similar experiences in the future.
“I once sent in money for something I saw advertised in the back of a magazine, but the merchandise was of such poor quality I was sorry I’d bought it. I’ll never buy anything that way again; once bitten, twice shy.”
If you fall in love with someone and that someone rejects or hurts you – once bitten – you may be very, very reluctant – twice shy – to let yourself fall in love again.