撕心裂肺不如百毒不侵
[sī xīn liè fèi bù rú băi dú bù qīn]
The term '撕心裂肺' means being extremely hurt emotionally (to the point of heart-rending pain), while '百毒不侵' suggests a strong resistance against all sorts of harms or disturbances. Altogether, it expresses that it might be better to have a toughened heart to avoid being hurt too deeply by emotional turmoils.