Americans say the 'corner' and 'coronor' almost the same. Is it true?
Well, they shouldn't!
Well, maybe they do, like: "cor-e-ner"
I can see how much alike they must sound. There is a brief little "uh" sound between the "cor" and the "ner." And when we are speaking quickly, sometimes those little bits of sound just about disappear!
You're right, they sound almost the same. "Coroner" is a little bit longer, but other than that, I could see how someone could find it confusing
Here's my two cents worth on this one...
Corner has 2 syllables.
Coroner, and note the correct spelling, has 3 syllables.
Either can have various regional pronunciations.