I'm guessing your wife has little to no experience with double-action pistols. The P3AT is listed as having a 5 lb trigger. That is right in there where it should be - maybe 6 lb before break-in. There are relatively few double-action pistols that come with a lighter trigger and many that are heavier. The small size of the gun means a narrower trigger which can make it feel harder to pull.
As opposed to a single-action pistol with a safety, that will have a shorter and lighter trigger pull, that moderately long 5 lb trigger is the only thing standing between her and a negligent discharge. It is supposed to require a deliberate pull on the trigger.
With this particular trigger system, there is not much that a gunsmith can do to lighten the trigger pull. A lighter hammer spring, if it were available, would cause light strikes. Polishing the trigger bar can make the pull a bit smoother and possibly a pound lighter, but a few hundred rounds down the pipe (break-in) will also improve it some.
What your wife needs is more trigger time. Unfortuanately, due to it's high power to weight ratio, the P3AT can be a little unpleasant to shoot, especially for some women, I think. I would suggest that you have her practice for a while with shooting gloves to increase the comfort level and allow her to get in some more trigger time. She will get accustomed to the trigger. Unless for some reason yours has an uncharacteristically heavy trigger pull (doubtful), it's really not that bad. Clean, lube, shoot, repeat.
P.S. Take her to Walmart and get a pair of Bell bicycle gloves. They have some with exposed fingers and gelpads right where she needs them to absorb some recoil making trigger time more bearable and fun.
Snap caps are also a great way to practice with the trigger pull, look for the red aluminum brand, A-zoom. Also I put some eletrical shrink tube on my PF9's trigger and that really helped for me, the PF's trigger used to pinch my finger between the trigger and trigger gard.
Golden Loki is a member here and is a gunsmith so maybe he will offer his opinion.