Good points Sree - However, I still think Abhi is jumping to conclusions..There is a difference in whether the world believes the girl who was "raped" and if Abhi and Simran do. The difference is that Simran *knows* Sid, the world does not. If I put myself in that situation - I know I would not have been able to comment on such happenings/accusations if the person were unknown to me, but if the person were really close to me and I trusted the person, I would have trusted the person (I think and hope so anyway)! Here Simran knows and *trusts* Sid so I see nothing wrong in her showing her confidence on Sid. As for her trusting Sid and not having trusted the others as much - well, even she admits she has made a mistake in not trusting Shankar.. She does not want to repeat the very same mistake in Sid's case - more so since she has known Sid since he was a child! I think after having learnt from bitter mistakes in the recent pasts, she is more cautious and is also willing to trust people whom she has known for so long.
I do not think Sid being her future SIL has much to do with it. If it were proved beyond doubt that he had raped a girl and if he really had, Simran would have agreed and admitted to it and would never support him. She did not even tolerate it when Aastha (junior) had cheated in an exam. In fact it took a while for Simran to forgive Aastha on that, she was so furious..So, I don't think the situation would be different if it were her SIL - that too when the crime involved is much more heinous than cheating in exams.
I however would give Abhi a benefit of doubt for his behaviour only because he did not know Sid as well as Simran did..As I wrote in some other thread, maybe he is aware of weaknesses towards the opposite sex.. He has been in that situation himself - though he was never so perverted that he would commit a rape.