Well yeah, what she wanted was obviously fickle.
How she may have worded it to the dragon is a completely different story.
As far as she thinks, IMO, a "hot boyfriend" or "perfect boyfriend" is basically her true love. Let's face it, if she were looking for less would she really need to go collect the dragonballs? She's after forever, but her only requirement so far is that he's gotta be hot-damn-diggity, because like you said she's pretty shallow at this point. So if she asked for her true love, man she would be in for a surprise.
It's like if you wished to be married to someone. That would happen, but you didn't cover what you may have really wanted, like an actual loving relationship. Your husband/wife may cheat on you constantly or divorce you right away, ya know?
Or in this case, blow up the planet.
Not that I believe in "true loves" in da real world, but what's canon is canon.