How to say it 'it must be' in Spanish?

Question

E.g - it must be very difficult to learn 3 languages

- are these right?

1) tiene que estar muy dificil aprender 3 idomas

2) debe estar muy dificil aprender 3 idomas

Answer 1

DEBE DE SER MUY DIFICIL APRENDER TRES IDIOMAS

Answer 2

I'd put "debe ser muy dificil....."

Answer 3

Tiene que or debe, but use ser, not estar.

and debe does not take a "de"  just debe ser.

Puede ser is more, like, it should be or could be.  You could use it, but it's a little softer.

Debe ser was my own first thought.

Answer 4

no, estar is commonly used but it´s incorrect, estar should be used to establish location or a condition like being sick "estoy enfermo" "tiene que estar muy enfermo"

tiene que SER muy dificil ................

or debe or puede, etc