Shorting Selling is the trading methodology used to sell a Security/Share that you do not own and buyback by the end of the day. This trading technique works under the belief that the Security/Share being shorted is poised to decline by the end of the day so that it can be bought back at a lower price.
Example:
Let’s say a person is shorting / short selling 100 shares of Company ABC at Rs.100, thereby making Rs.10,000. This is excluding brokerage and any other services charges levied by the broker. By the end of the day, the same share declines to Rs.90 and will be brought back. Thereby making a Rs.10 profit per share and a total profit of Rs.1000 (Excluding brokerage and any other service charges levied by the broker).
Net-Net by the end of the day you would own 100 shares of Company ABC bought at Rs.90 per share, and you would have already made a profit of Rs.1000 by shorting the share at Rs.100. This is excluding brokerage and any other service charges levied by the broker
Once a share is shorted there is no option not to buy the share, as short selling by itself is a combination of a SELL trade and an automatic BUY trade.
Short Selling should be used only in a bear market when you have a clear indication that a particular share is poised to decline in price. Never short a share based on rumors as you might lose your money if the share price increases by the end of the day instead of declining.