原来一直都是我一厢情愿
[yuán lái yī zhí dōu shì wŏ yī xiāng qíng yuàn]
It means 'So all this time it was my wishful thinking' - describing an epiphany where you acknowledge certain hopes have always relied on unreciprocated feelings; realization of harboring expectations which aren't shared mutually with another leading to heartache.