Do as empasis

"Kublai Khan does not necessarily believe everything Marco Polo says when he describes the cities visited on his expeditions, but the emperor of the Tartars does continue listening to the young Venetian with greater attention and curiosity than he shows any other messenger or explorer of his."

I think this kind of DO have the function of emphasis on "continue" as my dictionary says but what kind of thing does this emphasis concretely mean? The do implies the feeling of "Although Kublai think Polo might say untrue story as well, he keeps the great attention to what Marco says"?

The sentence is quoted from http://www.ndsu.edu/pubweb/~cinichol/CreativeWriting/323/CalvinoInvisibleCities.htm