I think people are willing to say don't force her but hey

as he said he thinks it's more of a fear of pain thing then not wanting to do it

it's not so much convincing her to do it but convincing her it won't hurt ( side note here it WILL hurt if you not very careful so her fears here are justified)

I don't know what to tell ya for advice but generally you can try and ease the fear in her but even that doesn't mean she'll do it, I wouldn't push it though you'll just end up pushing her away from the idea

if anything ease into it jusy play around with a few fingers at first, not with the mindset of "getting her ready" but just for the heck of doing it I mean it's a good starting point to showing that it can be pleasurable without her feeling pressured into doing more