I've had a root canal done. It was possibly the most painful experience of my life, before during and for a while afterwards. It was three years ago and I can still imagine the pain in a very real sense now.
The worst (best?) bit was that the nerve wouldn't die, and they couldn't get it all out at first. They kind of had to pack everything back in (along with a morphine coated dressing) for a couple of days and send me home to "let it die properly" so they could remove it.
The procedure itself is basically, torture. The anesthetic they use helps a bit, but the vibration that shakes your skull as they butcher you causes it's own sort of pain that the anesthetic doesn't touch. And it takes a while. Quite a while.
I'd think carefully before sharing that experience with her if I were you
