I've taught many adults and children to ride a bike. I also use the technique of lowering the seat and removing the pedals. Handling has to be learned before pedaling.

A good way to assuage the fear is to go to a soft grassy area, rolling slowly, and deliberately falling on your side. Do this yourself before telling your student to do the same. Once she realizes that falling is quite survivable, she can take better risks.

But the big question is how motivated she is. Let her take the lead. Make offers, and let her take or leave them.

One smaller question is whether she wants you as her teacher. Sometimes, these things are better taught by someone who is not a family member.