In the prince machiavelli advises ruler to

What advice does Machiavelli give about why a prudent ruler should not keep promises?
A ruler should not keep promises because if the promise endangers your life it shouldn't be kept, or if the reasons for the promise to be made are gone. (People are also very untrustworthy.)

The most important benefit of having a difficult amendment process is that people can never amend any part of the constitution very easily. the makers of the constitution wanted the amendment process to be deliberately hard, so that no person can amend easily for his or her personal benefit. i hope the answer you.