You may not understand the question, but at least, you will have a one word answer.
Yes or I agree – there is also 예 (ye), but ‘ne’ is considered more polite.
a ni yo
No or I do not agree – this is the simplest way to say ‘no’. As in English, there are multiple ways to indicate a negative, but this is the basic way.
It is worth noting that in Korean unlike English, when you say ‘yes’ or ‘no’, you are indicating agreement with the person, as opposed to the statement. For instance, if you are hungry:
“You are full?” “No, I am hungry.”
“You have not eaten?” “Yes, I have not eaten.”