Often we need words to explain how probable something is. Lets look at some examples.
There are dark clouds in the sky. It will definitely rain
There are no clouds in the sky. It will certainly not rain this morning, but perhaps it will rain this afternoon.
Are you going on holiday this year?
Maybe. We may visit my mother. Or we may go to see my friend in France. But probably we will just stay at home.
Will Kevin go to the football match on Saturday?
Definitely. He always goes when City are playing at home.
It is likely that City will win. but it is unlikely that they will win the Championship this year.
Will Kevin go to the pub with George after the match.
Probably he will, but it is possible that he and George will come back to the flat to watch TV.
Will Kevin remember to buy flowers for Joanne's Mum's birthday?
And will Joanne be cross with him?
Here is Doc Bates singing Absolutely, Positively, Maybe. Sorry, Doc, women are like that!