Looks like JES-sye to me. Come on, this is a silly spelling of an infantile name that works as a nickname, but sounds childish as the actual name of an adult.
Jessye Norman one of America's greatest singers puts all the pop/rock ones totally in the shade with the beauty of her stunning operatic voice.
-- Anonymous User 3/8/2010
Jessye? Really? Ugh, this is more retarded than Rubye! I normally don't call things "retarded", but it's appropriate here. It looks like Jess-EYE, or rather "Jess! Bye!" Thankfully, (and I know a few Jessica's), I don't know anyone who uses this spelling, which means it's not common. I hope it stays that way.
And for my opinion, I think this is probably kept as a nickname in the youth. If you like this, you'd probably be better off calling your daughter Jessica, then stylising "Jessie" in this way. But, she'd probably grow out of "Jessye" eventually.