Question

I do not believe ................. his story. (in/on)​

Answer 1

in

i do not believe in his story

Answer 2

The answer to the question ‘I do not believe ................. his story. (in/on)’ will be: I don’t believe in his story.

The word ‘in’ in the sentence is used as a preposition.

A preposition is a word that governs the other words in a given sentence and precedes a noun \a pronoun and expresses the relation of the reposition used with the other words in a sentence.

For example, She is found of ice-cream