the art of governing is to keep its affairs before the mind without weariness, and to practice them with undeviating consistency means?

The correct answer is, the meaning of the quote is that the the exercise of govern a city or a country is to maintain the public issues of the people at the utmost importance, despite of any ither circumstance, distraction or tiredness. And doing it on a consistent basis because is what good government does in any situation.

The quote "The art of governing is to keep its affairs before the mind without weariness, and to practice them with undeviating consitency" is included in the book "The Analects", attributed to Confucius, written by Lao-Tse. In chapter 12, is when Yen Yuan is asking the Master about these important political issues.