深知付出不够不知爱你多久
[shēn zhī fù chū bù gòu bù zhī ài nĭ duō jiŭ]
The phrase 'Knowing that my efforts are not enough, I am unsure for how long I can love you' expresses a profound feeling of inadequacy about one's ability to sustain or support a relationship over time. It reflects a sentiment of sincere but uncertain dedication, hinting at both vulnerability and affection.