To gain trust, a sportsbook must be trusted and can provide unique services which have licenses and certificates. As well as having cooperation with international agents to provide the most complete sportsbook services.
Have you ever heard about 1xbit? I think 1xbit fulfill your criteria (especially about license) to be trusted sportbook, but what is the fact? They are not trusted at all. Licenses is not a guarantee to be trusted gambling site, most early crypto casinos had no license but they can get good reputation because they can prove themselves that they are reliable and worth to trust.
As far as I know, 1xBit doesn't have a gaming license, otherwise they would have listed it on their website. They aren't even registered as a company anywhere, so they can't have a license, IMHO.
Unless you mean 1XBET's license, but 1xBit denies any relationship with 1XBET (which is, of course, a blatant lie).