Giles and Jenny have a strong reaction to one another when they first meet in I Robot, You Jane. It's apparent that they come from different worlds -- he's into the book thing, and she's cyber-woman. She ribs him about being an old-fashioned boy, and the stage is set for some romantic liasions in Season 2.
The attraction between these two is very evident in Season 2, beginning with When She Was Bad. They haven't seen each other over the summer, and they're eager to chat. In the next episode, Some Assembly Required, Giles is struggling with how to ask Jenny out. I think this may be a problem common to many guys, but who knows. Alls I know is, I ain't no Jenny Calendar. Not yet. Anyhoo, when Giles beats around the bush and blows his chances, Jenny surprises him by asking him out. Way to go, Jenny! Giles and Jenny are an item pretty much until The Dark Age. That's because it's in this episode that Jenny becomes possessed by the demon Eyghon. Needless to say, she's a bit shaken up by the whole incident, and it doesn't help that the demon was a skeleton from Giles's past...Jenny keeps her distance from Giles for a few episodes. It's in the episode Ted that Jenny is finally able to come to terms with what's happened, and she and Giles are reunited by the end of the episode. Basically, she'd been cold to him early in the episode when he was hanging around, trying to see how she's doing. So she follows him later to apologize. She's followed him to the park, because he's on vamp patrol duty since Buffy's under duress (check out the ep. page for this to learn why). Anyhoo, Jenny saves him from a vampire when she picks up the crossbow and shoots it. First she hits Giles in the backside area, then she gets the vamp. Unfortunately, the love-thing isn't fated to last very long... Everything's pretty good until Innocence -- this is when everyone learns that Jenny is really Janna Calderash, of the Romani gypsies! Giles feels betrayed, as does Buffy, because Jenny wasn't up front with them about who she was and why she was in Sunnydale. Turns out she was sent by her people to keep a watch on Angel, and to keep Buffy and Angel apart so that Angel's curse wouldn't be broken. Giles shuns Jenny...in BBB, Jenny tries to make amends with Giles, but she falls under the love spell and ends up making a play for Xander. It's in Passion that Giles's and Jenny's relationship seems to be on the mend. First Jenny lets it slip that she's in love with Giles Yikes!, and later Buffy tells Jenny that Giles misses her. Giles and Jenny decide to chat that evening, and Jenny says she'll stop by his place later on. Unfortunately, Angel comes to school with the notion of killing her, and he does. He snaps her neck, then places her dead body where she'll be found by Giles -- in his bed! Giles tries to avenge her death by seeking out Angel in the hopes of killing him, but Buffy comes by to stop him, lest he get himself killed. Naturally, Giles isn't over this, and probably won't be for some time, if ever. He never had the chance to tell Jenny that he loved her, and a part of him will always regret that. In fact, he thinks Jenny's ghost is the one haunting the school in IOHEFY...but it's not. Giles seems to see Jenny one last time in Becoming II; Dru's hypnotized him to see Jenny in the hopes that he'll be persuaded to spill the secret of how to bring forth Acathla. He's shocked and sickened to find out that he's been tricked into kissing Dru and telling her the key to the demon-bringing ritual.
