Well, don't forget that Jackie has also been stalking Kim and accused Kim of using magic right to her face.

Kim has a pretty good reason to not like Jackie. Jackie has been trying to blow open Kim's biggest secret, a secret that - if it ever got out - could get Kim killed or much worse.

I mean, just to be fair here. Kim isn't very nice, but she also doesn't owe Jackie anything after Jackie tried to antagonize her earlier. And she certainly doesn't have to trust that Jackie's invitation to ice cream was sincere instead of just a trap to get closer to uncovering Kim's secrets.