What to do with a scared kitten HELP

Guys, I'm all out of ideas. I have two sister kittens about 12 weeks old. We adopted them about 2 weeks ago. One is grey, the other is black. The grey one is a perfect angel. The black one seems to be getting more and more scared of my girlfriend and I everyday. She will always run/scatter out of fear when approached. She is ridiculously scared of anyone that comes close to her. She hides under the sofa. When she was first adopted, she was a bit better in that she would come out to play A LOT with the other kitten. Now, she hides under the sofa scared out of her mind most of the time . I used to be able to trick her out from under the sofa with her toys, or a laser pointer. Now she just doesn't budge. It's weird though. If I can get her picked up and on my lap, i can usually get her to calm down and even fall asleep! As soon as I put her down, it seems like she's forgotten who I am! I'm all out of ideas. It seems to be getting worse by the day. HELP!

I don't think you should try to push the issue because it will just traumatize the cat.

I've had to babysit cats in the past who didn't know me. The one thing that always draws them out is food because they have to eat at some point.

Maybe you can re-establish trust if the kitten sees that you're the one who is providing food for when she's hungry. It will create patterned behavior where she'll associate food with you.

If you try to approach her when she doesn't need anything from you, you'll imprint those feelings of negativity and seeking to be aloof or independent of you. Those will be the memories the cat will remember and govern its behavior.