To be fair all fiction is, well, fictitious and a romance that was firmly rooted in things that are likely would probably be quite boring.
However one plot line that seems to pop up in the summaries of romance novels is someone inheriting something (usually a ranch or sometimes a hotel) on condition that that marry someone in particular, or marry someone unspecified within a certain time period or have to live in the inherited property for a certain length of time before they can sell it (which usually involves giving up a demanding career that they come to realise was making them miserable). In the books there never seems to be any question that the deceased person can do this, but I have often wondered if it's even legally possible. I know funds can be left in trust but I've never heard of anyone with a trust fund that is contingent on them marrying or living in a particular location and nowhere else.
Another one that pops up a lot is being inadvertently snowed-in in a remote cabin either with a stranger or two people that can't stand each other. That's one that I particularly enjoy, there's something very pleasant about being cosy inside when the weather is harsh outside. There is always plenty of food and firewood but only one bed, and the plumbing never freezes. This has also never happened to anyone I know, but it seems a bit more possible than the previous scenario. My Mum was changing planes in Gatwick on her way back to Ireland from somewhere when she got snowbound for a few days. She managed to get a hotel room to herself though, it wasn't at all romantic. 