One of the most surprising revelations in The Last Jedi was the fact that Rey's parents were not in fact one of the many suggested possibilities that fans had speculated about since the credits rolled on The Force Awakens. It was a dramatic twist that actually added more depth to Rey as a character than any of the alternatives could have, and Rian Johnson should be applauded for the bravery.
Still, the director doesn't seem entirely sure that it's the end of the story. Though Kylo Ren seemingly confirmed to Rey that she came from nowhere and that her parents were unremarkable, Johnson has hinted in an interview with Huffington Post that it could all be open to interpretation:
“What’s going to make life hardest on her? It would be the big ‘I am your father’ twist [from ‘The Empire Strikes Back’]. And same thing with Rey and her parentage. The easy thing would be, ‘Yes, your parents are so and so and here’s your place in the world. There you go.’ The hardest thing she could hear would be […] ‘No, you’re not going to get the answer. This is not going to define you. You’re going to have to find your own place in this world. Kylo is going to use that even as leverage to try and make you feel insecure, and you’re going to have to stand on your own two feet.’
“Anything’s still open, and I’m not writing the next film. [J.J. Abrams and Chris Terrio] are doing it.”
Inevitably, that "anything's still open" comment will spark speculation once more, and it really isn't out of the realms of possibility that Kylo Ren would have misled Rey to try and tempt her to align with him after the slaughter of Snoke and his guards. After all, Star Wars has a long history of characters lying to serve their own agenda, and adding a further revelation concerning her past would be a particularly saucy way to spin the final film in this trilogy.
And when you look at their exchange in that sort of light, it does feel a little like emotional manipulation:
Kylo: Do you want to know the truth about your parents? Or have you always known? And you’ve just hidden it away. You know the truth. Say it. Say it.
Rey: They were nobody.
Kylo: They were filthy junk traders who sold you off for drinking money. They’re dead in a paupers’ grave in the Jakku desert. You have no place in this story. You come from nothing. You’re nothing. But not to me. Join me. Please.
Still, Johnson may only be consciously fanning the fires of hype for JJ Abrams' Episode 9 while holding his hands up and admitting that he has no control over the story - even if Abrams was said to have loved his The Last Jedi script.
For now, we'll just have to continue speculating, which is a shame because Star Wars fans famously HATE doing that.