My favorite pronunciation of this name is the one in which the O is pronounced as such, with some influence from the R, instead of “kuh.” Hence, core RE nuh and not kuh RE nuh.
I knew a girl with this name, she pronounced it "cuh-RINN-uh". I don't like it much, it sounds kind of harsh. If I heard "cuh-REE-nuh", I'd assume it was Carina.