A discussion on why the ups and downs before 1950 and why only positive inflation after 1950 is beyond my area of expertise. But part of me does wonder on the accuracy of the chart because it shows several spikes much higher than the highest level of inflation past 1950. I'm assuming those are due to wars.
Granted, those people may not have their savings in assets denominated in that currency (if they have any savings at all), but - in line with what you write - investment decisions shouldn't (and rarely do) have anything to do with "trust". Consider that security-thinking folks more or less define a "trusted person" as "somebody who can undermine your security".
"Technology" in economics also comes to mind as something that causes a lot of confusion.
There are other reasons including weak governments that had much less control over the economy and a lack of knowledge about how the economy worked but the money supply was a big part of it.