There's an old joke in Washington that if you want to be really successful, the one thing you need is sincerity, and if you can fake that, you got it made. I don't know if that works in Washington, but I can sure tell you where it doesn't work.
Over my career, I've watched hundreds of salespeople deliver thousands of presentations, and if they aren't authentic in the story that they're telling, a client and a prospect will sniff that out in a heartbeat. You might as well wear a sign around your neck that says, “Hi, my name is... and I suffer from terminal impostor syndrome.”
It's even worse if you're pitching from a stage because you have so little time to capture the attention and the imagination and to connect with that audience. So, before you go out and you talk to your next prospect or client, or you think about even giving a presentation from the stage and pitching one to many, which is a really, really great way to bring in clients and prospects these days, spend some time thinking about what your authentic story is . . . because you can't fake that. And if you fake that, you'll lose your audience in the blink of an eye.