countries that no-one cares about (such as the UK),
...because they only think of themselves and their foreign policy is "look the other way/don't get involved". Sometimes I think that might be a good thing.
It's not because of that. It's because the only countries able to cause serious problems for the rest of the world on their own are the US and countries controlled by crazy people.
Places like the UK, France and Germany may be powerful, but they're not powerful enough to project their power with such ease that they can be
guaranteed to avoid losing as long as they have enough support. Only the US can do that. As a result, no-one really cares about what they get up to. They'll never harm anyone on their own.
Countries run by crazy people may not be as powerful as the big European democracies, but they don't have to worry about public opinion when they declare war, meaning they can do all sorts of crazy things that democracies can't do.
Really though, I think it's unrealistic of most nations to NOT suspect nations they're dealing with. China certainly has reason to be suspect of N.Korea and vice versa. I'd also probably say "the truth hurts, live with it" and leave it like that. Unfortunately most cultures that focus more on personal presentation rarely deal with problems they have and would probably consider what happened an act of war.
I've always thought that cultural practice is extremely childish...
And it looks like China is actually really pissed of with NK. In fact, it looks like they want Korea to be reunited, with the capital in Seoul.