What if I believe my company is worth Rs 500 crore and someone says Rs 300 crore?

Both numbers can be honestly held. Each comes from a method, usually a multiple of earnings compared with similar listed companies, and from assumptions: which year's earnings, which peers, how much growth and how much risk.

Arguing about the answer rarely moves it. Ask which assumption differs and what evidence would change it, then build that evidence. No one can promise the final price; it is set at the issue. What you can build is the evidence behind yours.