好心当成驴肝肺

1. • to mistake good intentions for ill will

     saying

Character by character

• 好(hǎo)good
• 心(xīn)heart
• 当(dàng)at or in the very same...
• 成(chéng)surname Cheng
• 驴(lǘ)donkey
• 肝(gān)liver
• 肺(fèi)lung