Before answering this question, we reckon it is reasonable to give NFTs and smart contract definitions.
An NFT is a digital representation of a physical asset, such as a work of art, real estate, or even a car. The non-fungibility makes these tokens exclusive and can also be used to create scarcity. They are unique and cannot be copied or modified by anyone else.
A smart contract is a program that runs on another platform, such as Ethereum or NEO, and performs specific instructions when certain conditions are met. They are self-executing with detailed directions written into their code as well as the terms and conditions of the agreement.
Smart contracts are computer protocols that facilitate, verify and enforce the agreement between parties. In the context of NFTs, the smart contract guarantees that the digital asset you buy is exactly the same as the one described in the token sale. It also ensures that you own the asset you buy.