Practice, Practice, Practice....
Modern PPK's seem to be hit or miss with some people. My experience has found the following problems:
1 - Magazines: There are lots of cheap and older versions available, but the factory magazines work best.
2 - Ammo: I generally use WWB at the range, but it creates feed problems about 15-20% of the time in my PPK/s. Using Federal's round nose ammo or almost any HP have solved the problem of the ammo catching on the feed ramp.
3 - Limp Wristing: The blow back action and full stainless steel design can feel brutal to new shooters, and I've found they experience more failures than others. A firm grip high up the beavertail (watching to ensure no slide-bite) works well.
Ever since working these problems out, I have experienced no failures at all. So keep practicing and if you don't run into any problems I would have no problem trusting it.