What is the best way to indicate the reliability of the ad source?

Question

css

There is a trade announcement service for MMORPG players.
How to indicate (by what sign, by changing the font weight of the name, or by changing the background color of the ad) that the source has been verified and is "trusted"?
Something like a VKontakte checkmark is needed, but what is the best way to do it?
Where, how and what?)
Thank you in advance.

Answer 1

What's wrong with the checkbox?