Everyone but me in this thread is too intelligent that my stupidity stands out...

Leaving that aside, I have an incredibly stupid question about English.
Google says there's the difference in nuance between ”don't understand him" and "can't understand him" but I'm not 100% sure...

The first one carries a connotation that you don't understand what he says because you have no information or you don't know anything so far, so you are likely to understand what he says when you get the information from someone.

On the other hand, the second one has a nuance that you understand the meaning itself of what he says but you don't understand why he says such a thing.

Am I getting it right?
If not, would anyone like to dumb down the subtle difference between the two for me?


>>213527644
ガーネット(garnet) the theme song of 時をかける少女 is brilliant.
Every time I listen to this song, I almost cry.
https://www.youtube.com/watch?v=l08O1IGT5pw