我本是薄荷凉入心我非薄荷为何心凉
[wŏ bĕn shì bó hé liáng rù xīn wŏ fēi bó hé wéi hé xīn liáng]
'Being mint originally cools the heart, yet if I am not the mint, why has my heart become cold?' It metaphorically refers to losing passion and feeling emotionally distant without external reasons.