你不在我心你怎知我心痛
[nĭ bù zài wŏ xīn nĭ zĕn zhī wŏ xīn tòng]
'If You're Not In My Heart, How Could You Know My Heartache' addresses deep pain that isn't fully understood by those outside it. It suggests a plea for empathy - acknowledging the complexity of heartache which cannot easily be comprehended unless personally experienced, expressing longing for true understanding from someone else.