In korea, passing by a Korean restaurant, I noticed the food menu they provide, and one of them was a traditional Korean food deodeok-gui(grilled deodeok(a variety of bellflower)), and I thought they may not sell it in Austrailia. So suddenly I came to make an expression "I think they wouldn't sell deodeok-gui in Austrailia", but I'm not sure if it's correct to express presumption or uncertainty. As Raymott said, there's no rule to tell the following three, but how can I tell one from the others? Does it all depend on context? But at least I should know any helpful reasons.

If "would" is used as an opinion, my sentence will be "I'm sure they don't sell deodeok-gui, but I'm saying it in less blunt way", but I tried to use it as presumption, so does it work? Or do I have to say "I think they might/may/could not sell it"?

would: Opinion or hope
  • I suppose some people would call it torture.
  • I would have to agree.
  • I would expect him to come.
would: Presumption or expectation

  • That would be Jo calling. I'll answer it.
would: Uncertainty

  • He would seem to be getting better. (less certain than: He seems to be getting better.)