What is the difference between Zero Trust and Zero Knowledge?
They are quite different ideas.
You don't have to trust the other party for a transaction to take place because the system ensures neither party can cheat.
For example you want to exchange token1 for token2 but you don't trust anyone who has token2. You can just use a smart contract to do the trade without trusting the other party. You only have to trust that the system (smart contract and the blockchain) works as intended.
Blockchain is very good for zero trust systems.
Used often in conjunction with something like "zero knowledge proof" where you can prove to possess something without revealing what it is (zero knowledge for the other party about the exact possession). You can for example verifiably claim to know number
x without revealing what the number
Some more info: https://en.wikipedia.org/wiki/Zero-knowledge_proof