But, if I send a certain amount directly to a public key adress, then what guarantees that the other half will send the same value in the other crypto?
Should I rely on the benevolence and honesty of some random internet strangers? That doesn't sound reasonable.
Yes this is the way it is with all centralized exchanges, choose the most reputable and move your crypto out immediately. Decentralized exchanges and Atomic Swaps are the future alternatives.
Thanks for enlightening! I was expecting a different answer, but I guess the world is different than my needs.