Finally, I am new to the terminology on this forum. I do not get this whole whitewashing business.
How did Sahiba whitewash Seerat?
After Sahiba replaced Seerat at the wedding, the whole siyappa was about Angad believing Sahiba was the one who forced Seerat to leave, that it was Sahiba who wanted Seerat's place all along, that there was no boy with whom Seerat ran away, Seerat was not guilty
He believed Sahiba was evil
Even when Sahiba was trying to save Seerat from killing herself, even after Sahiba threw herself into the river to save Serat, Angad still believed this was Sahiba's doing
Sahiba then made a promise to prove that there was a boy with whom Seerat ran away in 7 days. She did this to clear her name, not to whitewash.
So what whitewash?
At the gurudwara when Angad was confronted with Garry-Seerat drama, he refused to believe it and again blamed Sahiba.
After that the challenge changed from "Sahiba took Seerat's place at the wedding because she wanted Angad" ---> "Garry was the one Seerat eloped with"
Seerat was pretty honest that evening when she confronted Garry and admitted to her own actions.
So, what whitewashing?