Welcome to OFCC, Bethany.
I'd recommend that you take a few minutes to search through old posts here that are specific to women's holster concerns. There's some really great threads that contain a lot of good material as well as both in- and out-links.
"Comfort" is very subjective. What I find to be comfortable may be even more so for another individual, completely unbearable for another, or just so-so for yet someone else. Even when everything else is held the same - the holster, how it's carried on one's body (both "clocking" as well as the set-up of the holster), other gear considerations (belt, undergarment, etc.), the gun - the simple fact that comfort is a subjective evaluation makes it hard for any advice to truly be universal. And while most of us men can be lumped into one of a few different body shapes, for women, there's usually much more variability...and this makes it even harder.
There are, however, some generalizations that can be made.
First, good support gear is essential. If you intend on waist-side carry, a good belt is an absolute must. Being a woman and perhaps having certain dress considerations, this can make things somewhat harder for you, but again, there are some very good old threads here that can help guide you. To get you started, give this one a read:
http://www.ohioccwforums.org/viewtopic. ... hilit=belt" onclick="window.open(this.href);return false; . I also put in this category under-garments, including the under-shirt. I'm an untucked-T kind of gu
y, but when I train, I usually wear an under-shirt so as to avoid chafing at the holster/firearm area due to sweat/heat and my draw-stroke. Here, I like to wear undershirts that will not bunch/pull easily so as to insure both a good draw as well as, even more importantly, safe holstering - UnderArmour's compression shirts are thus a favorite.
Second, while full-hardshell Kydex (or other plastic) holsters, unlined, tend to offer the lowest profile, this will still depend to a large degree on belt-clip positioning. With the belt-clip positioned on top of the pistol, it will add bulk to what is already the bulkiest part of the gun/holster combo. To further lower carry profile, look for an offset clip - however, be aware that offsetting the clip can reduce stability. With a gun as small as the P238, this shouldn't be much of an issue, but if you plan to exercise while using this carry option, it should still be a consideration. Leather backed half-Kydex shell holsters tend to give the wearer better comfort (however, again, this is totally subjective - I know plenty of people who carry full-hardshell Kydex holsters, IWB; and while I prefer a full leather holster for IWB comfort, ironically, one of my most comfortable carry setups is my PM9 in a Garrett Industries Silent Thunder Slim II full-hardshell holster), the leather side - particularly if it is of thicker material or if it has an additional lined backing for further increasing comfort - can add to the profile of the holster. That said, a thinner leather half is not without its shortcomings, either: it's less resistant to stretching (which will occur over time and will narrow or even close the mouth of the holster, upon draw), and the sweat-shield can easily collapse over the mouth of the holster and make the re-holstering stroke a little more complicated. Typically, with full leather holsters, you'll need to pay a pretty penny and/or endure a longer wait-time to get one that's thin enough yet also rigid enough (to prevent the mouth of the holster from closing, once the gun is withdrawn).