The correct answer is: "convince the people that the Consitution contained safeguards against goverment becoming too strong".
This excerpt is an evidence of the deliberations that preceeded the enactment of the US Constitution which, in this specific case, are related to the first considerations of the principle of division of powers, which nowadays is a basic element in every democracy. The principle was introduced by an Enlighment philosopher: Montesquieu.
The principle of the division of power establishes that the power of the states needs to be divided in 3 branches: legislative (Congress), executive (Goverment) and judiciary (Court system). Moreover, a system needs to established to that each of the branches supervises the other two, so that none of them gathers enough power to overrule the others. In the current US, such system is denominated The System of Checks and Balances.