How and why use "It has to be" in English.
Posted: Thu Oct 27, 2011 6:56 am
How and why use "It has to be" in English. 
We use this structure to describe what must be, that something is required or necessary to be a certain way. A set of instructions for an essay (as an example) might read "It has to be 1500 words."
It can also be used to convey disbelief:
"Apparently that type of food isn't healthy."
"What? It has to be!"