Fabulously

In an extremely impressive, wonderful, or stylish way; amazingly well.

From the adjective 'fabulous' (from Latin 'fabulosus' meaning 'legendary' or 'incredible'), plus the adverbial suffix '-ly'. The Latin root 'fabula' means 'story,' so fabulously literally means 'in the manner of a fable or legend'—something almost too good to be true.