If you say お前…なぁ(Omae… nā: you...) what is it that you're trying to say?
Context: A girl cuts ties with her best friend, telling her it's because she's selfish.
My doubt: なぁ could indicate a strong sentiment because they split apart or maybe she's saying the real reason is that it's for her own good (and not being selfish as she had explained).
So it could be:
You, I wonder...
You, (strong sentiment because they're not friends anymore).
I don't even know if it's actually true that it's because she's selfish. Unless that particle somehow denies its credibility it would mean that she's simply selfish.