I agree that affirmations do not work to change core beliefs. But all core beliefs are based on a kind of a logic - what changes those beliefs is to have them challenged with a better logic that gives us that "aha!" moment - an epiphany. In that moment we can and do change our core beliefs and almost immediate change can come about.
I'm not sure I like the logic that I will deal with it to be honest - because it doesn't silence the fear that I cant or might not - it feels like it still requires something from me that I dont have. I prefer the idea that I dont have to deal with it - they can deal with not liking me or me having an anxiety attack. I deny myself any escape route as part of my recovery - a better plan when you think you have anxiety coming and wonder "what will I do" is to plan to have an anxiety attack and a public one at that, hell I plan to tell everybody and let them deal with it - and maybe even have a little sit down and rest right there (should it actually happen). It always goes away when I plan that. You dont have anxiety attacks when you genuinely couldn't care less - thats the secret sauce.