是我太丑配不上你
[shì wŏ tài chŏu pèi bù shàng nĭ]
Translating directly as 'It's because I am too ugly for you', it can show self-denial and low self-esteem in front of someone admired, or reflect social pressure due to appearance. Sometimes it is used humorously by the owner, but at other times it represents genuine insecurity and self-consciousness.