Every time you place a "Bettor" mode bet on SportX, you are sending a transaction to the Ethereum blockchain. Sending a transaction with your wallet requires you to send some of your Ether (ETH) so that it gets processed on the blockchain.
Transactions are non-reversible, so your wallet will ask you to review and sign the transaction before. This will display technical details such as the data you are sending and the cost you are paying. If it all looks good, then hit accept and your transaction will be sent out to the Ethereum Network.