Well she's a princess from a planet called Almerac and while she did fall for Clark, it was more than just physical attraction. She wanted a mate who could produce her strong children to keep her family line going. And left her betrothed to find him. And at the time, for plot reasons, Earth women couldn't breed with Kryptonians(and I'm assuming vice-versa), so she considered herself a perfect mate as they were genetically extremely compatible. But he saw her behavior and didn't want kids who were basically borderline evil. So Brainiac ends up destroying her planet, and she has to serve him but then rebels and joins the new Justice League, hoping that Supes will give her a shot since she's a good guy now and did far more good than bad. But he's married to Lois so he still turns her down. She even swore revenge on him for shooting her down more than once. She's a tragic character, but I really enjoyed her. They didn't get to dive too deep in the show, but in the comics you go from hating her to loving her to hating her and back and forth until she sacrifices herself for the final time to save the entire universe from Brainiac 13.