You will need to demonstrate motivation, and what makes you the best candidate. Also think of some personal experience or connections to Korea. Why should they take you and not one of the many other applicants? What do you aim to achieve by doing this? Try and think how this will help you professionally.
For an exchange program it doesn't necessarily mean you need to know the language, but you should express knowledge in it or declare interest in learning it if they're going to consider you seriously as it is one of the major parts of cultural exchange.
The main thing they will look for is high motivation, so just make sure you think hard about what you really want and how you will get there, and they will consider giving you the opportunity.
Hope this wasn't too obvious and helped a bit~ good luck exchanging :)

I heard it was quite high level questions, but i heard it hard but not sure exactly what are the question...but at the of it they asked her to introduce herself in korea/anything related to korea or hangul.

But this interview not exchange programme but an intervie to continue master in korea.

#sorry if it not helping much