Cute little bear pup.
Underwoods 140Grain has the 1500fps+ velocity to elevate the kinetic energy, with light recoil that allows quicker/more follow up shots. By all accounts, defense against a bear is a close encounter of one or two maybe three shots. Wildbill is right on target with his points, and recommending Underwoods 140gr extreme penetrator. And, don't aim by following the head bobble of the bear, center mass will do it, either gets the head, or spine, or heart, as their bodies don't bobble sideways, they bobble vertical through the kill zone where it doesn't matter if you hit the brain, spine or heart. The Glock 40 has a plastic stock, and not much recoil and rise, not at all like a .44 mag all steel revolver that takes longer to get on target with follow-up shots. Don't bother with hardened lead bullets, go for Underwoods solid copper ones.