A friend of mine told me this, not sure if it's true. Are there actually any fact that prove this?
I would say no. The U.S. was heavily involved with Europe economically, and had strong diplomatic ties to both the United Kingdom and France. The U.S. had decidedly wanted to remain neutral for most of the war, in line with the Monroe Doctrine, which was a foreign policy statement which stated that the U.S. would keep itself out of European affairs. The U.S. also broke off its diplomatic relations with Germany due to their use of unrestricted submarine warfare following the British blockade. The final straw between the U.S. and Germany was the Zimmerman Telegram, a telegram from Germany to Mexico, intercepted by the British. In it, the German Foreign Minister to his colleague, the German Minister to Mexico, offered U.S. land to Mexico in exchange for Mexico joining the German cause. Understandably, the U.S. was incensed, and formally declared war on Germany only some 41 days after President Woodrow Wilson was made aware of the message.