Do You Respond When Someone Askes You to Give a Talk or to Make a Presentation?

When some one askes you to give a talk or to make a big presentation, and you're plagued with self doubt, do you respond to that by doubling down on the amount of time you're spending in preparation? You know, there there are elements of that. When i am giving a talk on the impossitive phenomenon, a talk that i have given more time than i can count, i still prepare as though i have never given the talk before. And it's because i want to make sure that when i give the talk, that people hear me and experience me as being an expert.