you have never seen
Nunca has visto morir a un hijo tuyo.
You have never seen one of your children die.
— El hombre de la tierra (2007)
¿Así que nunca has visto la cara de Giovana?
So you've never seen Giovana's face?
— Hoy Quiero Volver Solito (2014)
It's something you've never seen before.
Te prometo que será algo como nunca has visto.
I promise you it will be something like you've never seen before.