The litotes "not to neglect" is an understatement to emphasize that the writers want Artaxerxes to do what they tell him to do. Alternate translation: "Be careful to do this" (See: [[rc://en/ta/man/jit/figs-litotes]])
Artaxerxes uses a question to tell them that he understands that he will lose taxes and honor if the city is built. Alternate translation: "You must make sure that this threat does not grow and cause more loss for the royal interests." (See: [[rc://en/ta/man/jit/figs-rquestion]])
Danger is spoken of as if it were a plant that could increase in size. Alternate translation: "danger to become worse" (See: [[rc://en/ta/man/jit/figs-metaphor]])
The words "the royal interests" are a metonym for the king himself. Alternate translation: "cause more bad things to happen to the kings" (See: [[rc://en/ta/man/jit/figs-metonymy]])