"To trust the source" means to believe and have confidence in the person, organization, or information that is providing you with something. Full definition
We will be the preferred and most trusted source for breed - specific information about the health, behavior and training of German Shepherd Dogs. (germanshepherdcenter.org)
Finally, I would argue that unlike «the casual reader,» the avid reader will look for trusted sources of information about book quality. (studiotendra.com)
Finally, you should seek out career development programs from trusted sources in the industry. (medreps.com)