My favorite all purpose revolver is a 3" SP101 .357, as I prefer the balance and sight radius over shorter barrels, and is easier to store and carry than a 4".
I installed a Wolf 10# trigger spring on mine while leaving the return spring stock, which made the trigger very acceptable for both carry and target practice. Also installed an XS Big Dot front sight for fast target acquisition, and Diamond Pro grips for my large hands.
Whatever revolver you choose, make sure it has a set of rubber grips that fit your wife's hand well.
And do consider the SP 101 in .327, as .32 longs have mild recoil for target practice, the .32 H&R magnum is a carry round equivalent to a .38+p, and who wouldn't like an extra round in the cylinder.