How long has she been with you? Perhaps she has a long lasting fear of hands that you will have to patiently persuade her is not necessary. Very gentle, slow coaxing with lots of sweet talk and treats just to approach your hands. Perhaps just touching the ends of your fingers to get a treat first rather than trying to do a full on hold where let's face it, they give up their freedom. That takes a lot of trust and we all know that needs to be earned on our part and just because she might have trusted another that much doesn't mean that she automatically trusts you the same. Try eventually putting the treat in your palm so she needs to lean in to get it, rather than between the fingers.
Back off would be my guess. Don't wave hands at her that's scary. Be grateful for the trust she does show and the rest will come when she is ready. Be prepared for a long haul so that anything sooner is a bonus. Just let her lead the progress.
I don't know if you are male or female but do you wear rings that might be different. I am female and if I wear a new outfit or jewelry Syd is very wary. A new dressing gown just a few days ago took several hours before he would approach my shoulder, and when he was new to me a different colour top would send him right back. I am sure he thought I was a different person.