嘴硬心软不讨喜我知道
[zuĭ yìng xīn ruăn bù tăo xĭ wŏ zhī dào]
It literally means “I know I am stubborn in words but gentle at heart and thus unpopular”. It shows a self-awareness of one’s own behavior traits, indicating that the speaker is straightforward and kind-hearted but does not gain favor with people.