How does DeFi pay interest?

Could you elaborate on the mechanisms behind how DeFi, or decentralized finance, pays interest? Specifically, I'm interested in understanding how these platforms generate returns for investors without relying on traditional financial institutions. Do they utilize lending protocols? Do they involve staking? How do these interest payments work in a decentralized, trustless environment? What are the risks associated with earning interest in DeFi, and how do platforms ensure the security and stability of these interest payments? Your insights would be greatly appreciated.