that's really
Now that's a challenge.
That's good.
Eso sí que es una locura y yo loca por escucharte.
That really is crazy, and I'm dying to hear you.
— Las diabólicas (1955)
Oye, eso sí que es una buena idea.
Hey, now that's a good idea.
That is truly magnificent.
Eso sí que es un problema difícil de resolver.
That is a difficult problem to solve.