They would all come across at a puja for dev's health; in front of alot of poeple.
He would call kaajjal characterless, and curse her by saying that no man will want to marry a woman who had a relationship with another man, and that's why she was in hotel room with dev and then she fabricated the entire story.
Dev in heroic mode; trying to shut dhruv up will take sindoor's plate and put it in kaajjal's maang to prove her purity.
Then he would later realize that he wasn't thinking at that time but it would be too late.