Engagement is in three weeks and my parents already paid for the hall. How do I stop this now?

Cancelling now will cause a genuine crisis at home, and your father’s fear about his reputation in the office is not something you can just wave away as old-fashioned. He has invested money, reputation, and emotional capital into this match since Holi, and the wedding cards in his study represent a social contract he expects you to honour. But going through with an engagement you know is wrong will only make the eventual separation harder, messier, and far more public than a cancelled hall three weeks out. You need to speak to your parents today, not by hinting at cold feet or asking for more time, but by stating clearly that this marriage cannot happen. Sit them down and say, I know the hall is booked and the cards are printed, but I cannot go through with this engagement because I know we are not right for each other, and stopping it now is better than a divorce later. Expect anger, panic, and immediate worry about what relatives will say at the office and in the neighbourhood. Let them be angry. Let them absorb the shock of lost deposits and awkward phone calls to guests. You will have to bear the weight of their disappointment and absorb the fallout of the social embarrassment they fear. That cost is steep, but it is a finite pain compared to starting a life you already know you want out of.