When two stars have “chemistry,” we tend to think of it as basic animal magnetism. And maybe that’s the essence of it. Yet when a romantic movie works, even a synthetic magical rom-com trifle like “Irish Wish,” what draws us into the chemistry isn’t simply the actors’ sexy connection. It’s that the two characters have chemistry, and that each actor has it with the audience. That’s the connection Lindsay Lohan and Ed Speleers have in “Irish Wish. The movie is as frothy as the foam on a pint of Guinness, as formulaic as the last disposable Netflix rom-com. Yet these two make you believe that they belong together, and not every romantic comedy does that.

“Irish Wish” takes place in a version of the real world flecked with fairy-tale fantasy. But before we even arrive at the mystical part, the first sign that the movie’s...