We already have a couple of firsthand stories, just by the less than tiny number of people in this very thread, of Goyim who become “Orthodox” and married real Jews.
How many more there are that others (not in this thread) are aware of. And how many untold thousands more there are that haven’t yet been discovered (and may never be discovered), that are halachic Goyim, many of them female, married to frum Jews and giving birth to more Goyim who will intermarry frum Yidden, and no one realizing.