Reuters News follows the 'Trust Principle' while putting together its News stories, keeping it factual, vetted through multiple sources and unbiased. And in the rare case of a rumor being reported, it would be explicitly stated in the text of the story.
One would find rumors more in Social Media or Web News, and such stories can be filtered out using the News Source field.
Can you please elaborate on your question. If you are asking about the filters that you can apply to the News query, please see News API documentation - which allows you to custom select the keywords to filter out unwanted noise.