How do new platforms earn users' trust in the beginning?

Many people test a new platform with a small transaction before deciding whether to use it more regularly. It's a simple way to check whether the overall experience feels reliable.

Using as an example, what do you think encourages users to take that first step? Is it transparent communication, positive user feedback, responsive support, or something else?

From a business perspective, what do you think has the biggest impact on earning early user trust?