you don't know it
Lui vuole sempre apparire, non lo sai?
He always wants to show off, don't you know?
— Aquarius (2016)
Non lo sai ancora ma ti abbiamo organizzato una festa a sorpresa.
You don't know it yet, but we've organized a surprise party for you.
Tu non sai quello che dici, non lo sai, non lo sai!
You don't know what you're talking about, you don't know, you don't know!
— Addio mia concubina (1993)
It's better if you don't know.