IPA: /dɪˈlaɪt.fəl.i/
KK: /dɪˈlaɪt.fəl.i/
In a way that brings joy or pleasure.
The children laughed delightfully at the clown's tricks.
Delightfully → It is formed from "delight" (from Old French *delit*, meaning pleasure or joy) and "-fully" (meaning full of). The word "delightfully" means in a manner that is full of pleasure or joy.
Think of experiencing something that brings you great joy or pleasure, which is what 'delightfully' describes.