Where did you get this story? He only signed for Dortmund last year because Dortmund is a team who plays with young players and he was going to get alot of playing time. He rejected other big teams because of it, including Barcelona. So why would he suddeny want to join a big team like Madrid or Barcelona and why would he reject Barcelona?
And PSG is never going to give Verratti, he's to important for the team. Neymar doesn't change this. And people are not waiting on Di Maria, he's already 29.
It's all over the web. British, French, German, Spanish websites such as bleecher, MD, etc all reporting the same thing. Best case, they are all using the same unreliable source.
Then again that was how the Neymar "rumor" started.
Dembele is not rejecting Barcelona since Barca has not made an offer to BvB yet, at least not recently.
Madrid is making an offer or at least targeting.