Verb + 긴 할거야?

Let's take a look at the pattern Verb + 긴 할 거야(?). This pattern is used when someone promises or intends to do something you doubt they will keep because that’s how you personally feel about it. In English, we say something like are you really gonna do it? It carries the nuance I doubt you will so I am asking. You are asking with the intention to make them fulfil what he or she said. Simply attach to the verb stem and add 거야 which is the future form of 하다.

돌아오긴 거야?
Are you really coming back?
(I doubt you will)

갚긴 거야?
Are you sure you’re going to pay me back?
(I don’t think you will)

오긴 거야?
Are you really coming (to my party)?
(I feel like you’re not)

도와주긴 거야?
Are you really gonna help me?

해주긴 거야?
Are you really gonna do it for me?