No such comments are found in _Nina_.
Second, the story is set in Prague instead of the British isles.

Third, the hero and heroine are already in love and engaged to one another at the opening; we are not told any details about their falling in love.

The hero, Anton Trendellsohn is a successful businessman in his mid-thirties--not the typical Trollopian hero in his early twenties, still finding himself, and besotted with love.

Anton is rather cold as lovers go, seldom whispering words of endearment to Nina.

But it is the fourth difference which really sets this novel apart and makes it both a masterpiece and an enigma.