In a happy or cheerful manner; with happiness. / By good chance; fortunately, successfully. / With good will; in all happiness; willingly. / (archaic) By chance; perhaps.

(idiomatic) A period of time, imagined never to end, in which (typically) a loving couple live untroubled, happy lives together. / A story with such a happy ending, such as a romance novel or fairy tale.

(idiomatic, often preceded by "they lived") Happily until death; used in a formulaic ending for fairy tales.