Here’s my thinking, based on lessons I’ve learned the hard way introducing my wife to the world of handgun shooting.
Because of your wife’s hand strength issue, a revolver might be a better choice than an auto. There’s no slide on a revolver to have to rack.
Even if she can manipulate the slide, many women also have grip size issues with double-stack auto pistols. This negatively affects gun handling and recoil management. A single-stack auto like a Kahr TP9/T9 or SIG 239 might work well for small hands.
I would most definitely not recommend a lightweight/airweight (aluminum/scandium frame) revolver in .38 or .357(such as S&W 442/642/340/342/37 or Ruger LCR) because of recoil issues. If you put one of these in her hands and she fires it she may never want to shoot anything you recommend again.
A good choice might be a S&W all stainless j-frame (640/649/60) or a Ruger SP-101. All of these weigh about 23-25 oz unloaded, and soak up recoil better than a 16 oz airweight S&W 642 or a Ruger LCR. This heavier weight makes for a much more pleasant shooting experience which means she might be more willing to train with the gun. If hand size is an issue you can find lots of grips for the 649/640/60 to acommodate small hands. Crimson Trace makes a number of types of lasergrips for these guns. My wife has a 649 with Crimson Trace LG-305s on it, and she likes it very much. The biggest drawback on these guns IMO is limited capacity, only 5 rds.
And I’d recommend .38 ammo versus .357, even if they’re so chambered. In .38 +P the Speer 135 +P Gold Dot short barrel load is a pretty good one as is Corbon’s DPX +P load.
If .38 +P loads give too much recoil for her, then there are various standard pressure .38 loads available. With them you may sacrifice either consistent expansion or sufficient penetration, but you’ll get lower recoil and blast than with +P loads. Even if she keeps the gun loaded with +P loads she could train primarily with standard pressure loads which are cheaper and more pleasant to shoot than +P loads.
A carbon steel or stainless S&W K-frame revolver in .38 or .357(Models 10/13/15/19/64/65/66/67) might work too. Here you’re looking at unloaded weights of about 30-35 oz(more weight = less recoil) and a 6 rd capacity. These would be easier to shoot than even the all-stainless J-frames or SP-101, but their weight may cause her to fatigue easily too. Crimson Trace makes lasergrips for them too. Same comments as above on ammo apply here.
Does she have any female friends who shoot handguns regularly? In my experience a woman can often help another woman pick a gun better than a man can.
Is there a clean shooting range in your area that rents a good variety of handguns? If so go there with your wife (and her female shooting friend) and encourage her to shoot whatever she likes.
A basic handgun training course (preferably with a female-friendly instructor) might be a very good thing for her to attend prior to buying a gun. Her experiences gained during the class could then inform her choice of a handgun.
The most important lesson for me in the process of helping my wife pick a gun was that it’s got to be her choice of gun not mine. I have a strong personality and probably unknowingly exerted too much influence on my wife’s choices. This lengthened the process and cost us extra money as we went through a series of guns for her.