我是你的傻瓜你是我的笨蛋
[wŏ shì nĭ de shă guā nĭ shì wŏ de bèn dàn]
It humorously translates as 'I am your fool; you are my idiot.' It's a light-hearted and playful way of expressing mutual affection, especially in the context of love, where both parties see themselves making foolish choices over the other person.