没心没肺的现在掏心掏肺的曾经
[méi xīn méi fèi de xiàn zài tāo xīn tāo fèi de céng jīng]
A reflection on personal change, where past actions seemed careless ('carefree' or without concern), whereas now those experiences feel deeply heartfelt - indicating regret or appreciation for past naivete.