You can assure he has not told the truth in a single thingthe seven cities are seven little villages?

The statement suggests that the person in question has been consistently dishonest, as they claim that the seven cities are merely seven small villages. This implies a significant underestimation or misrepresentation of the cities' true nature. Such a claim undermines the credibility of the speaker and raises doubts about their overall integrity. Therefore, it can be inferred that their lack of truthfulness extends beyond this one assertion.