A .22LR at realistic range with good shot placement (the result of lots of training) could be very effective.
A larger, easier to control pistol in the Walther PPK or TPH size would be easy to control and easy to conceal. If your wife is OK with SA then the aluminum alloy Beretta 71 is the way to go. So reliable, the Mossad/Shin Bet used it as well as the Israeli air marshalls.
Google Mordechai Rachamim if you want to read about what a determined fighter with a .22LR pistol can accomplish.
A larger, easier to control pistol in the Walther PPK or TPH size would be easy to control and easy to conceal. If your wife is OK with SA then the aluminum alloy Beretta 71 is the way to go. So reliable, the Mossad/Shin Bet used it as well as the Israeli air marshalls.
Google Mordechai Rachamim if you want to read about what a determined fighter with a .22LR pistol can accomplish.