you don't know
Tú no sabes lo preocupado que estoy.
You have no idea how worried I am.
I know something you don't know.
Tú no sabes dónde está, ¿verdad, Plumas?
You don't know where it is, do you, Plumas?
— Paddington 2 (2017)
You don't know.
¿Nené, tú no sabes que para pagar ese libro voy a tener que trabajar un año?
Nené, don’t you know I’m going to have to work for a year to pay for that book?
I know something you don't know.
Tú no sabes por lo que yo he pasado.
You don't know what I've been through.
— मुन्ना भाई एम बी बी एस (2003)
Tú no sabes con quién estás hablando.
You don't know who you're talking to.
You don't know that.