I think "assunto" would be better translated as "matter".
My dictionary translates assunto as subject,matter or plot. So I imagine it would really depend on the situation to which it refers. Tough stuff this indeed is without a tutor!
Agreed, unless the context is school-related.
Shouldn't "affair" also be a good translation for "assunto"?
That could work... but not for all meanings of the word "affair."
Also accepts: "this subject is very important".