그래요? - geu rae yo? - Oh, really?; Is that so? gureyo? 그래요. - geu rae [yo] - Really; That's so

jeongmal in english is really or very. You can also use Jinjja. I hope it helps you ^_^

http://www.youtube.com/watch?v=GWJmMKPJHr0 :D