谁的微笑里藏着悲伤谁的悲伤藏在微笑里
[shéi de wēi xiào lĭ zàng zhe bēi shāng shéi de bēi shāng zàng zài wēi xiào lĭ]
In English: 'Whose Smile Conceals Sadness, Whose Sadness Is Hidden Within a Smile'. Reflects a philosophical and empathetic outlook on human nature, suggesting understanding and sympathy for those who hide genuine unhappiness behind cheerful appearances.