The Importance of Being Vocal About Your Business

I had lots of doubt, doubt or moments being like, huh, I don't know if anyone anyone would want this. Is it any good? Who am I to write a book? How would I market it when anybody actually buy it? Like is it worth me spending like these hundreds and hundreds of hours on something that might just flop? And by being vocal about it, people kept asking like, when's it coming out? "It took a long time to get it out, but finishing it was definitely what I needed in order to show me that this thing worked"