A few minutes of digging:
Game: Tales of Destiny for PSX?
Enemy: "False Ishtar" I'm guessing you're trying to find some girl named Ishtar but this one is actually a demon? Not sure.
Attack: Wags her tail to shoot out hearts, they have some kind of petrify effect I think.
I think this is the american port (read: less sexy, more censor)
the tail wagging hearts come out at about 1:00 in this video
can't seem to find much more info or gameplay than that though, the few videos of people fighting her are mostly just killing her.