In Plato, “Phaedrus”, I noticed this passage, In good speaking should not the mind of the speaker know the truth of the matter about which he is going to speak?”.
Here Socrates is about to go on to explain the sheer importance of truth in speaking. He goes on to give an example about horse and the fact that what is being said is to be judged and kept in opinion by the listeners. Ultimately, the truth becomes persuasion or that is what I gathered from this text. I agree in the way the speaker does have to be truthful in what he or she speaks or writes about. Suppose a speaker is giving a speech, and that individual is knowledgable in their topic. This in return would give him the full attention of the audience and their respect. Now, a speaker who gives listeners b.s. and the speaker can tell the audience is not buying it then persuasion may come into play. If the speaker does not give up and goes through with their false information then this may be up to the speaker to practice the art of persuasion to their audience. The main lesson after all of that being said is to be truthful because no matter what people will judge you based on character and how you execute.
Source: Plato, “Phaedrus”