菇凉本无心何必太伤心
[gū liáng bĕn wú xīn hé bì tài shāng xīn]
Loosely translated, it means 'since I'm heartless (have no intention), why do you feel so hurt?' Here 'mushroom girls' (菇凉, gulang) usually implies young women. This suggests apathy or trying to distance herself from romantic emotions; hence asking rhetorically why there should be any suffering since she has always meant well by staying detached.