“cause to have known me would mean that there’s a new me, and if you think i’ve changed in the slightest could’ve fooled me” can someone explain what these lyrics mean?

Meaning that if you understand me then that means you’ve thought I have changed but I really didnt

This sounds like a personal reflection on something you did. it is asking the hardest part, or a part you may have struggled with on an informal interview you must have done. it is also asking advice you'd give someone else for the process of completing an informal interview, so you should write something that would . for example, maybe the first thing they should do, something they should include.