百毒不侵万箭穿心
[băi dú bù qīn wàn jiàn chuān xīn]
Untouchable Yet Pierced By Ten Thousand Arrows. This expresses a sentiment akin to enduring multiple sorrows, pains, betrayals, and losses, remaining emotionally unscathed despite being exposed to numerous challenges and hardships—a tough heart, still capable of deep emotional experiences or reactions. In brief, invincible but not insusceptible to inner wounds.