(SPOILERS, but the title of the thread already told you that)
Her third wish was that she could love Steven (though she didn't know, at the time, that it wasn't really him) for who he really is. This opened quite a paradox, as how could the Djinn grant such a wish without revealing his true form? After all, Verdel ISN'T who
HE
really is. Since he can only go by the words in a wish, he couldn't alter that to be for who she thought he was, it had to really be for him. This also provided the Djinn with quite a conundrum. As he himself said, human love cannot be taken. It must be freely given. So, he knew that he couldn't really grant that wish. She really had to grant it herself, because she had to fall in love with him to fulfill it. Pretty interesting.
Proud member of the IMDb Ministry of Darkness
That's right, boysIT'S DOCTOR VENKMAN!!!

That they would stop making crappy sequels like this one!