who's going to tell her
Ulster is 9 counties , of the Northern Ireland counties 3 are in the Irish Repiublic the remaining 6 are in the statelet commonly known as " Northern Ireland "
it is in fact Northern Ireland will remain part of the EU for trading purposes
the EU is not occupying Northern Ireland ( somebody else is )
currently NI has tarriff free access to EU markets along with markets in england scotland and the principality of wales (they say they are a country but can't hold a referndum to leave the uk )