Swap prices for native swaps are determined by the DEX powering the underlying transaction. Additionally, gas fees are required to send these transactions on-chain. Gas fees and slippage settings can be configured under advanced settings. Refer to this article for more details.
The swap output is estimated, you will receive at least the “minimum received” (if you specified the From amount) or maximum sold amount (if you specified the To amount) or the transaction will revert if there is a large, unfavorable price movement before it is confirmed.