Whoa! What? I have understood that "le" was ONLY an indirect object pronoun, meaning "him/her/it/you". Meanwhile, "lo" I've understood to ONLY be a direct object pronoun, meaning "him/it/you". What you two are saying here completely blows all this out of the water. E.g. that "lo" and "le" could be used for the same part of speech in a sentence, resulting only in a shift in reference but not otherwise in meaning. This should not be the case if one is only a DO pronoun and one only an IO pronoun.
Can you please elaborate or offer a reference where I can dig in further with this?
Your thinking was correct, I just think FrederickEason and dwhl went on a tangent about a different subject.
Originally, FE was saying when you see the direct object lo, you should assume it means it when you have no context and when you see the indirect object le, you should assume him when you have no context. dwhl then asked if the indirect object le could also translate to her without context, and FE agreed it could, and edited the original answer. Hope that explains things!
If you put the cursor over the "lo" at the top of the page it says "it, you, or him." But they marked "You are never going to understand him" as wrong. It should be accepted. Going the other way. if you want to translate "You are never going to understand him" to Spanish then this is exactly how you would do it - "Jamas lo vas a entender."
[I go and find the Spanish grammar I got for $8 at the used book store]
You can either put "Jamás" first, or you can put "No" first, with "jamás" at the end: No lo vas a entender jamás.
Words that can be used in the same way to negate the verb are: nadie (no one); nada (nothing); ninguno (none); nunca (never); and jamás (never) as we've just seen.
You can also negate the verb by just putting "no" first:
No veo la casa.
(A Student Grammar of Spanish, Ronald E. Batcheldor.)
Although your translation "never are you" is literally correct, tranMinhNhut, English customarily places the subject, which is "you" in this sentence, at the beginning. Accordingly, the first thing you need to do is reorganize your translation so that thet the subject is at the beginning. Lo vas a entender/You are going to understand it.
The next issue that you need to understand is where it is possible to insert the adverb, which in this case is "never." In English, adverbs can either precede the entire verb concatenation or be inserted somewhere after the first helping verb and before the main verb. For example, You NEVER are going understand it/You are NEVER going to understand it. When there is more than one helping verb, there is more latitude about where the adverb can be placed within the verb: You NEVER will be able to understand it/You will NEVER be able to understand it/NEVER will you be able to understand it.
In these examples of adverbs that do not end in -ly, the adverb always come before the verb, and never comes after it. Note that the third example shifts the subject "you" to a position after the first helping verb and shifts the adverb to the beginning of the sentence because the adverb is modifying the not only the compound verb "will be able" but also the infinitive phrase "to understand it," which functions as an object in this sentence but still can be modified by the adverb "never." To put it more simply, the adverb "never" modifies the complete predicate, which is "will be able to understand it."
Finally, I just wanted to add that adverbs that do end in -ly can be placed after the verb when they are modifying the verb: I completely understand/I understand completely. However, when an -ly adverb is modifying the whole sentence, then it can also be placed at the begining of the sentence: Truly, I understand/I truly understand BUT NOT I understand truely. This last sentence, "I understand truely" has a different meaning, which is that my comprehension is correct. That is, you do not understand falsely.