情毒入骨便是最痛
[qíng dú rù gú biàn shì zuì tòng]
This means 'When Love Penetrates the Bone, It Becomes the Deepest Hurt' echoing a theme of deep pain from heartache that resonates very profoundly, describing feelings after experiencing deep betrayal, loss, or unrequited affection—the most excruciating type of emotional suffering.