Schiarita comes from the verb schiarire, meaning to clear up, brighten, or lighten. It's a beautiful and evocative word that paints a picture of clarity and hope.
In the song, Nicola di Bari sings, "La notte si è schiarita" (The night has cleared up/brightened). This phrase suggests that after a period of darkness or uncertainty, things have become clear and hopeful, mirroring the joy the singer feels from his love.
"La Prima Cosa Bella" is a tender, plainly-spoken love song. The singer picks up a guitar he barely knows how to play, but plays anyway, just to have a reason to sing for the person he loves.
The heart of the song is its refrain: the first beautiful thing life ever gave him was her smile. Everything else is scenery for that one idea, the blooming meadows, a star caught between the trees, a night that suddenly feels clearer.
He admits he doesn't have fancy words. "Love, love, love" is all he can say, and he trusts that she'll understand him anyway. It's a song about loving someone in simple terms, and meaning every one of them.