"Advertisements contain the only truths to be relied on in a newspaper"

This quote by Thomas Jefferson suggests that ads are the only dependable source of fact in newspapers. He suggests that the news and other content in newspapers need to not be trusted, as it may be prejudiced or unreliable. This is likely due to the reality that papers are often moneyed by marketers, and for that reason have a reward to release material that agrees with to them. In addition, papers may be influenced by political or business interests, which might lead to the publication of false or deceptive details. Therefore, Jefferson suggests that ads are the only trusted source of fact in papers, as they are not subject to the same predispositions and affects.