When we want to say what we think will happen in the future in English, we can either use will followed by the verb without to, or going to followed by the verb.
"What do you think will happen next year?"
"Next week is going to be very busy, I think."
"There won't be a rise in house prices next year."
"He isn't going to win the election."
Because we also use will to talk about intentions and strong decisions, we often use going to to sound less emotional.
"He won't help us" can mean that he has decided not to help us. But "He isn't going to help us" doesn't have this negative implication. It sounds more like a prediction and a simple, non-emotional fact- perhaps he isn't able to help us.
Predictions based on what you know nowWe can make predictions based on what we can see now. To do this, we use going to and the verb (not will).
"Watch out! You're going to hit that car in front."
"It's going to be a lovely day today – not a cloud in the sky."