Of course this won't be the happy end. Nothing shown says Murakami is a bad person, even if the internet armchair psychologists here seem to think otherwise. But she is still too opaque a character and hasn't shown any kind of passion, so the lights are on impending drama.
So here's how it'll probably go: Murakami just goes along with this relationship out of convenience like she did with her last one, Moritani will clue in on this and at some point it wont be enough for her. Explore tragic past/drama, overcome it together, true love, yada yada yada.