你说我不懂事我说你很懂事
[nĭ shuō wŏ bù dŏng shì wŏ shuō nĭ hĕn dŏng shì]
You say I'm immature, but I say you're very mature. This could reflect a conversation or disagreement between two people, one claiming the other doesn’t understand while asserting they do understand themselves.