"The hot oil smells very good."
Translation:La varma oleo odoras tre bone.
Someone actually explained this very well in another discussion. Basically, English is kind of stupid for using an adjective and not an adverb, as it should in that sentence. But that's because both verbs are the same word. In Esperanto, there are actually two different words. odori- to smell, as in, has an odor. flari- to smell, as in, to sense an odor. Bona is an adjective and bone an adverb, which is why they use it to modify the verb, odoras. If you wanted to say that the oil is good at smelling things, you could say, "La oleo flaras bone", which would be the equivalent of the English "The oil smells well." Hope that helps.
I know you asked this quite some time ago. But in case anybody reading this is wondering about the answer... I've been speaking Esperanto almost two decades and I found I have the same question. I've found several explanations, but they all strike me as "just so" answers. I'm not saying there isn't a good answer, it's just that I have not yet found one. The best answer I can give is that "odoras bone" is the common way to say it in Esperanto.
In English, we can say that something "seems good" or "seems to be good" but not "tastes good" and "tastes to be good." I'm sure the answer lies in there somewhere - deep in how the human brain processes language.
"Bona" priskribus la subjekton de la frazo "oleo" kiel "La bona oleo odoras" (la ordo de la vortoj ne gravas). Geaŭskulatantoj ne scius kiel ĝi odorus, nur ke ĝi estus bona (ekz. ĝi povus esti saniga, sed malbon-odora). Nur se oni uzas la adverbon (anstaŭ la adjektivon), geaŭskultantoj scias, ke la oleo estas bon-odora.
To me, the difference is there. In English "smells well" implies that it's subjective, I. E. A person has a keen sense of smell. Smells good is objective, an object with a pleasant aroma. This breaks my brain using "bone" instead of "bona". No comment so far has explained why this is so. Is this just common usage even though there is no evidence?
The first thing to watch out is that "smell" has two meanings in English and that these meanings are represented by different words in Esperanto. Flari means to detect a smell with your nose. Odori means to give off a smell. Your comments is based on a double meaning that doesn't exist in Esperanto.
Since posting elsewhere in this thread that I have the same question (after almost two decades of speaking Esperanto every day), I've discussed this with other fluent speakers online, checked reference books, and even had an opportunity to discuss it face to face with the author of PMEG.
So... with all that in mind, here's the explanation I would give now. First, don't try to think of it in English. Saying "smells well" will mislead your brain. Think that "odori" means to give off a smell. "Bona" would describe the subject, not the smell being given off - that's why we use "bone".
Quite honestly, my gut still tells me that it should be different, but this usage is very common - basically standard - so I must admit that something real is going on here and that my gut is steering me wrong.