the future( usually with the verbs: hope (надеяться), think,
believe, expect, imagine, etc; with the expressions: I'm sure, I'm afraid, etc; with the adverbs: probably( вероятно),perhaps, etc)I believe he will have to cancel his trip.
She'll probably be late.
2) for on-the-spot decisions
I'm so tired. I'll take a break.
3) for threats.
If you don't study hard, you will fail your exams.
4) for hopes, fears, offers, promises, warnings (предупреждения), predictions, requests (запросы), comments, etc especially with: expect, hope, believe, I'm sure, I'm afraid, probably etc.
I promise I won't forget you.
I'm afraid she will be busy tomorrow.
5) for things we are not yet sure about or we haven't decided to do yet.
Maybe I'll go to the cinema later.
Future Simple
will + V