Julietta? Why not
Giulietta, or
Juliette?
Personally, I'd use
Juliet but only as a mn, for two reasons. Firstly,
Juliet is the only
Juli- name I like, and one of my issues is that people shorten it to
Julie, which I really find very dull and trite. And secondly, where I live anyway, most people put the emphasis on the last syllable, which doesn't work for me at all.
I like
Tessa Juliet.