"I agree with you completely."
Translation:Ik ben het helemaal met je eens.
I see. I don't really know how to explain it, but I can try. I think it's like this: the finite verb always comes at the second place in a sentence. In this sentence the verb is 'met iemand eens zijn', but the part that conjugates, the finite verb, is 'zijn'. The rest of the verb ('het met iemand ('je' in this case)') comes at the end of the sentence. Most of the times, and in this case as well, the subject comes first. The object, which is in this sentence a bit "weird" ('het'), comes after the finite verb. That leaves us with 'helemaal', which is placed between object and the rest of the verb.
Ik / ben / het / helemaal / met je eens.
Subject / finite verb / object / rest of the sentence / rest of the verb
On a side note, if you want to say this in a negative way, be careful of where you place 'niet', because there are some different meanings.
- Ik ben het helemaal niet met je eens. - I do not agree with you at all.
- Ik ben het niet helemaal met je eens. - I do not entirely agree with you.
It's the "het" that I don't understand. What is it referring to?
"Ik ben met je eens" I would understand (a bit like "I am united/agreed with you"), though I know this is wrong.
"Ik ben het met je eens"… For and English ear, this sounds like "I am it agreed with you", and is really confusing. This makes the phrase hard to remember.
I would more easily construct it as "Ik ben daarop met je eens", and that's how my foreigner's tongue wants to say it. I just can't figure out why it's "het".