The reversibility of smart contracts is not guaranteed with NFT transactions. NFTs are often designed to be non-fungible, meaning they represent a unique asset that cannot be exchanged for something else. Once a transaction is confirmed on the blockchain, it can be difficult or impossible to reverse. Therefore, it is important for users to carefully review the terms of the smart contract and understand the implications of their transactions before executing them. Additionally, some NFT marketplaces may offer dispute resolution mechanisms to address issues that arise after a transaction has been completed. However, these mechanisms may not always be reliable or available in all situations.