Showmance vs. real romance?

How do you know if it's real? It happens in Survivor and Big Brother. But some showmance fail like Will and Shannon and Eric and Lisa. But some are real like Survivor's Rob and Amber. Now we have Boogie and Erika and Willl and Janelle.What's your opinion of showmance vs. real romance? Is it really real or fake just for TV, when the season is over, it ends.