心如柠檬好酸好酸心如薄荷好凉好凉
[xīn rú níng méng hăo suān hăo suān xīn rú bó hé hăo liáng hăo liáng]
'The Heart Is As Sour As A Lemon And As Cool As Mint' contrasts two feelings - heart as sour (displeasure/disappointment) and cool (fresh/comfortable/indifference). It might imply that this person's mood alternates between being discontented with the world (or some situations in life) and having an inner peace that offers comfort.