It's one thing to not trust any woman and it's an entirely another thing for Viaan to ask his employee Katha to undergo a loyalty test.
Amounts like 1 Crore or 2 Crores is a huge amount in today's times and it's not everyday that any person makes such an unusual demand.
Viaan could have simply refused her demand instead of agreeing for the same on the condition that she gives her consent for his indecent proposal.Viaan had no right to make such an outrageous demand whether it's Conditional or Unconditional.
He did not even ask Katha as to why she was demanding such a huge amount.He mixed his own personal feelings with Katha's Demand rather than dealing with the same in a Professional Manner inspite of being a Tycoon.
Viaan had let his personal views to cloud over his judgement.God knows what he was thinking during that time?
Katha on the other hand perhaps was in a desperate situation hence without thinking she agreed for the same This enabled Viaan to take advantage of her precarious situation.
Viaan's current actions has damaged his character arc unless the CV's wanted to portray him as a manipulator.Its no doubt makes it difficult to accept Viaan and Katha as some sort of a pair even if he redeems himself and that's perfectly understandable.