I think I saw promotional material with human Nam Shin waking up, so I don't think they will take that route. The main conflict will be Mom's wanting to get rid of NSIII and him feeling rejected. So Bong will be there for NSIII and they will develop romantic feelings. Unlike other people, I don't think that it is that crazy to consider a long term couple with the robot. We are supposed to believe that something as advanced as NSIII is created, and he can behave as a normal human, it is just that he is made of metal. Well, there are people in this world that marry old or unfertile people with whom they cannot have children. Fertility isn't everything for a couple's happiness. And there are also millions that will never really know what love is about and will live painful lives around humans that treat them badly. A robot that makes you happy is an improvement in my eyes. Anyway, in the end it is all about what So Bong wants.
Anyway, I think it is very unlikely that the writers will go for the happy romance route. That would be a very open perspective on relationships, LOL. I'm afraid that they will kill the robot since it is the easiest way to solve the complicated romance. As for me, I would be happy if the robot survives; romance is not essential, I just want him to find his place in the world and be accepted and have friends.