Its better than a .22 LR and probably a .22 Mag out of a short snub barrel.
I looked over the factory ammo and Fiocchi has a 100 gr LSWC it lists at 730 fps. That is probably from a 4 or 6 inch barrel so from the 2 inch it will probably be in the 600's.
Here is a Brass Fetcher gel test with the .38 Sp 148 gr Federal Gold Match wadcutter, also with a velocity around 600 fps.
Single shot fired at block, bullet penetrated to 16.0" and was found 'sandwiched' between the rear face of the gelatin block and the front face of the polyester bullet arresting box. Bullet recovered at 0.386" average diameter.
The recoil from this round was very slight, penetration depth was more than adequate, and slight expansion occured. I like it as a choice for recoil-sensitive shooters, using .38 Special snubnose revolvers.
The 100 gr .32 Long Fiocchi should give good penetration as well, I would like to see tests, but I'm fairly certain it will penetrate deep enough to be lethal.
Just remember that shot placement is crucial to the effectiveness of all handgun rounds, especially small ones like the .32 S&W Long.
For home defense, I would seriously consider getting your wife a 20 ga shotgun, even a single shot would be vastly superior to a .32 Long.