I'm reading a book and found there is a sentence. Is it correct? I'm not an English native speaker and I just feel Do you is more proper here. Just want to confirm.
I am confirming that you're not wrong and your intuition is serving you well. Do you want is not a MORE proper but THE proper way to say that. "Are you want" makes "want" sound more like an adjective or a noun of some sort, but "want" being an adjective or a noun makes zero sense in that context.
Here's a little reminder for you: the auxiliary verbs do, does and did (note that I said "auxiliary" as the usage of the verb do here is different from the way do is used normally when it's a regular verb) are always paired with verbs while different forms of the verb to be such as "are" and "is" are never paired with verbs. For more detailed information on this topic, follow the link in blue.