не понимаю, о чём ты

I don't understand what you're talking about

→ не
phrase Rare #34,587
I don't understand what you're talking about A conversational way to say that you do not understand someone's point or meaning. Literally, “I don't understand what you are talking about.”
RU: Извини, я не понимаю, о чём ты.
EN: Sorry, I don't understand what you're talking about.

Я действительно не понимаю, о чём ты.

I really don't understand what you're talking about.

Не понимаю, о чём ты.

I don't understand what you're talking about.

— Тар (2022)

Я правда не понимаю, о чём ты.

I really don't understand what you're talking about.

— Тар (2022)

Признаюсь, я не понимаю, о чём ты.

I admit, I don't understand what you're talking about.

Не понимаю, о чём ты?

I don't understand what you're talking about.

— Пиноккио (2019)

Я не понимаю, о чём ты.

I don't understand what you're talking about.