Whenever I see "årsak", "case of the year" comes to my mind :)
German "Ursach" is a useful link.
Is there a way to distinguish he will find vs. he wants to find?
I'm not certain, but I think you'd use skal instead of vil.
What's the difference between årsaken and saken? They both mean the case or the cause, right?
the origin of the problem ... is not accepted here.
Would that be really wrong?
Are the words opprinnelse and årsake different in meaning?
The cause of a problem and its origin can often be two quite distinctly different things. For example, the cause of death from covid-19 is greatly different from the ORIGIN of covid-19.