Thanks Brad, Elliott and DC Ron.
For the third couplet, I just wanna say that a good bossa singer (like Joao Gilberto) has always elegance (refinement) and it seems so natural for him. His voice is relaxed and muffled (In french, we say "voix feutrée"). And there's no vibrato! (Unlike some current singers who make it a competition...)
The singer, in the song, is happy to discover that this voice exists in her.