Maybe or may be?

из English Grammar Today

We use maybe and may be to talk about possibility. They are often confused because we use them both when we think that something is possible but we are not certain.

Maybe as an adverb

Maybe /ˈmeɪbi/ is an adverb and it means the same as perhaps. It is written as one word:

Maybe no one will come to the party.

Not: ~~May be no one will come to the party~~.

Spoken English:

In speaking, we sometimes use maybe at the end of what we say when we are making a suggestion which we are not very certain about:

A:
There’s something wrong with my PC. I can’t load my photos.
B:
It could be a virus, maybe.

Spoken English:

In speaking, we can use maybe as a response when we agree that something is possible:

A:
Ronnie and Linda are going to leave New Zealand in January.
B:
Why? I thought they were very happy there.

A:
I’m not sure. Perhaps they feel a bit lonely.
B:
Maybe.

We can also use maybe to express uncertainty in response to a suggestion:

A:
Would you like to have chicken curry for dinner?
B:
Maybe.
A:
You don’t sound very enthusiastic.
B:
I just can’t think about dinner right now. I’ve just had breakfast.

May be

In the phrase may be /meɪ bi:/ may is a modal verb and be is a main or auxiliary verb. Here may and be are two separate words, whereas maybe is one word: