1.
You use ~ to emphasize that you really mean what you are saying.
This is ~ the worst thing that I can even imagine...
= absolutely
ADV: ADV adj-superl emphasis
2.
You use ~ to emphasize that something really is the case, although it may sound surprising or extreme.
He’s changed since he came back–he seems ~ cheerful...
ADV: ADV adj, ADV before v emphasis
3.
see also positive