I think about my personal habits and preferences when building a business. I like to know who I'm buying from, do you?
I most likely won't buy something immediately if in my searches I land on a website that I've never heard of. The chances of me buying would likely increase if it came by an online recommendation from someone I trust. But even so, I would approach with caution.
I observe time and time again that people who seem to succeed have the trust factor built in. The trust generally comes from things like making friendships, being helpful and sharing helpful advice. Doing these things naturally builds up your network, your SEO, your mailing list, your followers - all the things that will help you when you come to launch your product.
Admittedly, I'm not a big fan of ads and validating ideas with a landing page plus paid ads. Of course, I know it works, in the right situation. For me this approach lacks the 'trust' factor. If I had trust in the person who was building the thing and I landed on their ad, then there'd be a higher chance I would buy. If I didn't know them, it would be highly unlikely that I would.
I fear that too many people rely on metrics and the results of ads on landing pages to validate their business, when what they should be doing is build up their trust value.
I fear trust is not built enough into how we businesses. People try to see business as black and white. When in fact businesses and people is so full of psychology and personal aspects that simply can't be measured.
I fear people who don't know you won't fully understand the bigger picture of what you are trying to build. They'll move on without any thought. Whereas those who even have a little bit of history with you will perhaps at least give you a 2nd glance.
Of course, trust is hard to measure and it takes time to build and that's probably why not enough people pay enough attention to it.