Hey!

Could anyone expletives me if there is such a verb like “certain“?

I’m reading the book and it goes “I was utterly certain that there would never be a wall”

I guess it has something to do with the “to be sure” but I haven’t found any verb definition of “certain”

Question

Hey!

Could anyone expletives me if there is such a verb like “certain“?

I’m reading the book and it goes “I was utterly certain that there would never be a wall”

I guess it has something to do with the “to be sure” but I haven’t found any verb definition of “certain”

Answer

Certain is not a verb, is an adjective. Cambridge Dictionary defines it as "having no doubt or knowing exactly that something is true."

I was utterly certain = I was completely sure...

Answer

As Enrique says, "certain" is an adjective.
Adjectives can describe nouns or pronouns.
In this sentence "certain" describes the pronoun "I".

Answer

Certain is the opposite of impossible.  It is impossible for you to hold your breath for one hour.  It is certain that you will take a breath.