你不真心对我何必真心待你
[nĭ bù zhēn xīn duì wŏ hé bì zhēn xīn dài nĭ]
This username expresses a sense of disappointment and retaliation. The user feels that if the other person is not sincere, they will also not be genuine in return. It shows some defense against possible insincerity or dishonesty from others.