我知道你不爱我但是我爱你
[wŏ zhī dào nĭ bù ài wŏ dàn shì wŏ ài nĭ]
Translating to 'I know you don't love me, but I love you'. A rather sorrowful declaration expressing unreciprocated love. The individual knows they're not being loved back, but continues having affection for that person regardless.