I think:
Giovanna Sophie (so-FEE)
Giovanna Soleil (so-LAY)
both sound like really good names.
I think as long as you pick a middle name that accents the second syllable, it will go well with the first name. (That is why ma-RIE works so well with so many names.)
Oh, and probably stay away from a middle name that starts with the "j" sound and ends with the "a" sound, since those are already in the first name. Otherwise the name ends up sounding like a made-up news anchor!
(In case you can't tell, I'm kind of a linguistic nerd... I love analyzing language! Self-proclaimed dork.

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