IPA: /ˈdʒɔɪfəl.nəs/
KK: /ˈdʒɔɪfəlnəs/
The state of being very happy and full of joy.
Her joyfulness was contagious, making everyone around her smile.
Joyfulness → It is formed from "joy" (from Old French *joie*, meaning happiness or delight) and "-fulness" (meaning the state of being full of). The word "joyfulness" means the state of being full of joy or happiness.
Think of the word 'joy' representing happiness, and remember that 'joyfulness' means being full of joy.