May be = In the phrase ‘MAY BE’ , ‘may’ is a modal verb and ‘be’ is a main verb or auxiliary verb.  Here, MAY and BE are two separate words whereas ‘MAYBE’ is one word.

• There may be a train at 10.00 a.m.
• He may be waiting for us.
• The Prime Minister may be addressing the people tomorrow through the media.

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

• Maybe she should consult a doctor.
• Maybe he thought foolishly she would give him all the happiness in life and continued his courtship despite his parents’ advice.
• Maybe he didn’t know that he was being trapped by her with proof and a case of molestation was being fabricated against him.
• Maybe my wife didn’t like it.
• Maybe they didn’t know you are a relation of mine.
• Maybe you received a wrong piece of information.
• Maybe he thought we were fools because we wouldn’t like to argue with him.

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Note:- Usually ‘Maybe’ is placed at the beginning of the sentence.