Jessica is well known as Jessica Jung the daughter of the wealthy businessman. But she goes by the name of Jung Sooyeon instead when she went to transfer to a new college in Korea after living for years in L.A. So people there doesn't really know who is the real her yet, where she came from, single or not, etc. 

lets not reveal much info here shall we? it wouldnt be fun then. pls go read the story further. hope it'll be a good story ;)