I am really confused when to use these two words and I find it hard to differentiate between them.

I have a firm belief/believe that he will come tomorrow.

Pls suggest some more examples that can help me to comprehend these two words .

Thanks.
It is simple, Rajesh:

Belief is a NOUN: My belief is that she will return to me someday. Christians were once persecuted for their beliefs.

Believe is a VERB: I believe that she will return to me someday. She believes that I am dead.
Here is one quick tip.

Believe - verb

Belief - noun

There are a few verbs in English that follow this pattern.

Relieve -

Relief -

Grieve

Grief

The ones ending with "ve" are verbs.

The ones ending with "f" are nouns.