Found 3 synonyms
merrily, gaily, blithely, cheerily, brightly, jubilantly, jovially, mirthfully.
thankfully, luckily, successfully, mercifully, aptly.
More happily synonyms
joyously, delightedly, fortunate, with pleasure, with great pleasure, with joy, with delight, safely, good luck,
Synonyms "happily" in the picture