President Wilson was reluctant to bring the United States into World War I for a variety of reasons. Some were associated with his own political ideals while others had more to do with his analysis of American national interests and American public opinion.
One thing that affected Wilson’s thinking was his perception of what American interests were. He did not think that America needed to involve itself in a war between European countries. He did not think that the US had any stake in the war. This feeling was augmented by the fact that the war did not appear to be about anything other than power. This was not, initially at least, a war of democracies against tyrannical monarchies. It was not a war of democracy against communism. It was not motivated by any ideals and was therefore not attractive to Wilson who was himself an idealist.
Wilson was also reluctant for domestic political reasons. First, he understood that Americans were not clamoring to enter this war. There were many Americans who supported the Allies, but many others (particularly those of German or Irish descent) who supported the Central Powers. Second, Wilson was committed to progressive reforms of American society. He worried that the resources and energy put into the war would destroy his chance of carrying out reform at home.
For these reasons, Wilson was reluctant to bring the US into the war.