Future Will

The Future will is used:

To make predictions about the future, usually

with perhaps or after the verbs believe, thing, hope....

"She'll probably be here tomorrow"

To talk about spontaneus decisions.

"We've run out of milk; I'll go and buy some"

For promises.

"I'll be on time, don't worry!"

For offers and request.

"I'll do the dishes after dinner"

For threats and warnings.

"I won't speake you again!"