What were the reasons for the countries to join league of nations?

The League of Nations was initiated at the Paris Peace Conference in an effort to stave off conflict and ensure that a war as devastating as World War I would not happen again. Under Woodrow Wilson's guidance, countries following principles of Liberal Internationalism joined the league on the basis of the premise that an eschewing of secret alliances, bilateralism and war mongering in favour of a the notion of a harmony of interests and multilateralism would result in an avoidance of arms races and self-interested action and, consequently an avoidance of war. The League of Nations was intended as the vehicle for this multilateralism. Unfortunately, it was shown to have been a flawed vehicle and efforts were largely thwarted by big power politics and continuing arms races which culminated in the Second World War.