mossberg 500 shotgun (pump)
double-barreled shotgun (non-pump plus can do two consecutive shots)
...if she isn't into firearms or shotguns, she should have no problem with the double-barreled shotgun(opinions differ but I wouldn't personally recommend the single shot)...
not sure if you are firearm savvy, but even non-enthusiasts have knowledge of what I speak: 'break-top' where you can put a shell in each side before closing it to fully load...when you shoot only one will shoot at a time. in an emergency you will still have a loaded shotgun after firing it...most will agree two shots is almost always enough...
*you can get decent deals, so if the price is too high you are doing something wrong w/regards to a shotgun
"Damn the torpedoes, full speed ahead!" -Admiral Farragut @ Battle of Mobile Bay 05AUG1864