Before I converted my Hybrid it did just fine on most trails. It's slower in turns so you'll be on the brakes more but with a good set of tires/tubes you'll be fine. The 29er tires are much more comfortable on single track stuff and slower on flat, gravel free, rocky off road stuff without many tight turns.

Edit: Also wanted to add that 45mm tires are only a touch smaller than 1.9" 29er tires. Granted the aspect of the tire is a little different, but if you didn't like the 700c hybrid, maybe you'd be happier with a 26"? Just depends on your riding style but I like staying stuck to the ground and rolling over stuff so the 29er/700c feel fits me.