To be fair, all you’d have to do is snap your fingers or dab after the conversation and you could tell that it fake. To tell it it’s real, you need a code word, for example: “alley-oop.” If you travel back to your past self, if someone needs to prove they’re in a time loop, or here. If you respond with “alley-oop,” you know it’s fake. If you don’t, you know it was real (as long as you now choose a random word that you swear to use in uncertain circumstances)