TC, I bet the real problem is that you give up too soon on one method when it doesn't yield results.
If you do the same motion for a long enough time, she will have an orgasm eventually. It's when you start doing shit like speeding up/slowing down/changing your method for no reason that things break down. Once you get a feel for how someone responds, you can start changing up your game. For now, just focus on the goal.
Source: had a few different women claim they couldn't O (with a partner), I proved them wrong and told them exactly why they couldn't.
She did say to remain constant. I tried this yesterday for about 10 good minutes before my finger started getting tired. >.> ---