What if Roshni and Aarav know each other. I mean what if she met him early on and he was the one that threatened Roshni that he would hurt Sid if she did not move away from him.
Roshni might have wanted to return back to Sid and her life within a few weeks and let all know that she is fine. But maybe she faces hurdles to get back, but in between she meets Aarav. He probably helped her. At one point he came to know about her relationship with Sid KHURANA. Which made him money hungry. So he made her an offer to help him to get his hands on the money or else. Roshni most likely refused. That might have pushed him to the point of anger. Roshni might have ran away and changed her identity thinking she was protecting the family she has left. Because Roshni was Aarav's ticket to Sid, and without her he couldn't get into Sid's house. The two years Aarav tried looking for her but he couldn't find her. He then gotten involved with Aanya knowing she is also RICH. But he got into the accident, maybe Roshni made it happen. Roshni has no idea about Anaya and Aarav.
ONLY SPECULATING!!