you have never seen
Te prometo que será algo como nunca has visto.
I promise you it will be something like you've never seen before.
It's something you've never seen before.
Apuesto que nunca has visto una mujer desnuda.
I bet you've never seen a naked woman.
— Estación central de Brasil (1998)
Nunca has visto morir a un hijo tuyo.
You have never seen one of your children die.
— El hombre de la Tierra (2007)