Maybe you’ve wondered about how to use the word “maybe.” Okay. Maybe, the compound word, is an adverb meaning “perhaps” or “possibly.”
The two words “may be” comprise a verb phrase meaning “might be” or “could be.”
Maybe I will go out tonight.
I may be going out tonight.
If you’re uncertain about using the word “maybe” or the phrase “may be,” you might try substituting “perhaps”: “Maybe Frankie will take me to the ball game” becomes “Perhaps Frankie will take me to the ball game.”
When the substitution makes sense, go with one word: “maybe.” When you are wondering whether you may be waiting for the wrong vehicle, you’re dealing with a verb and its auxiliary: “may be.” Two words.