I have both, (err the 239 is the wife's gun.) Yes the 239 is larger by quite a bit but it fits the hand better and has less recoil plus is DA/SA if that's a plus for you; the 938 is SA and is meant to be carried Condition-1. Depends on how you plan to carry it, the 938 is smaller and can fit in a pocket rig easily if you have bulky pockets plus it weighs less. The trigger on my 938 is a healthy 9lbs, or there abouts, and while it's smoothed out it doesn't match the crispness or precision of the 239's. Again, they're two entirely different purpose gun. For what it is, the 938 is a great deep-concealment gun...it is not a 'range gun.' The 239 is a great carry gun that is a fun range gun. Note both my 938 and the wife's 239 sport Houge rubber grips which improve the feel and control of the two guns.
ETA....Assuming the wife is looking to purse carry, the 938 would be my suggest proving you have a good stiff'ish holster (kydex or leather) insert or hidden compartment. My wife is looking to start carrying in her purse, (I know, not ideal but that's the only way she'll carry,) so I'm, looking to adapt a kydex shell on a velcro patch to affix her her purse.