Answer:
A supreme being is by nature, good
Step-by-step explanation:
With the statement, Rousseau is letting us know that he believes that there is a supreme being, a "maker of the world", and that everything that maker of the world makes, is good by nature, and can only get corrupted once it leaves the hands of the supreme being.
If he believes so, is because he thinks that the supreme being is a good, benevolent force, that can only bring good to the world.