Maybe is an Adverb The word “maybe” has basically the same meaning as the word “perhaps.” It can be placed at the beginning, middle or end of a sentence effectively to indicate that something is neither for certain nor definitely not going to happen. If you’re unsure whether “maybe” (one word) is what you should be using, try substituting it in the sentence with “perhaps.” If the resulting sentence still makes sense, you should have it right. Maybe, I’ll go to the mall later. >> Perhaps, I’ll go to the mall later.

Just to expand on the first person's answer, here are a couple of examples: Maybe: "Maybe she'll get a job at the hospital." May be: "She may be getting a job at the hospital." Maybe that context will help!

“Maybe” is an adverb meaning “perhaps,” so if you are uncertain whether to use this word or the phrase “may be,” try substituting “perhaps”: “Maybe she forgot I said I’d meet her at six o’clock” becomes “Perhaps she forgot. . . .” When the substitution makes sense, go with one word: “maybe.” When you are wondering whether you may be waiting in the wrong cafe, you’re dealing with a verb and its auxiliary: “may be.” Two words. Source : http://www.wsu.edu/~brians/errors/maybe.html

May Be is a Verb The differentiation between “maybe” (one word) and “may be” (two words) is not a matter of writing style. There is a distinct difference between the two, because they are different parts of speech. “May be” (two words) takes on a similar function in sentences as “could be” or “would be.” Alternatively, you can think of “may be” as working the same way as “may go” or “may live.” You have to realize that the construction of this term is much the same. If you’re unsure, as before, try substituting “may be” with “perhaps.” If it doesn’t make sense, then “may be” is the way to go. Jay may be stronger than Jim. . Jay could be stronger than Jim.