The text is from the Proclamation of Independence of the Democratic Republic of Vietnam written by Hồ Chí Minh in September 1945. Did Ho believe that America would aid Vietnam? If so, when would it become clear that America would be fighting a Cold War against communism?
Ho Chi Minh was a nationalist first and a Marxist second: even though he was a committed Socialist since the late 1910s, he didn't feel as if he was tied to the Soviet Union or the People's Republic of China in 1945. He believed that the United States would support Vietnamese independence and Vietnam would be free to practice self-determination and develop "Socialism with Vietnamese Characteristics," as it were.
Ho Chi Minh first petitioned the United States and France for Vietnamese independence in 1919 during the Versailles talks, but was ignored. After the Japanese occupied Indochina, Ho Chi Minh led an independence movement guerrilla force (the Viet Minh), and petitioned President Harry Truman multiple times, but Truman decided that backing France so as to keep them in NATO, and having an allied presence in South-East Asia was more important than self-determination. This was, of course, grossly hypocritical, given the contents of the Atlantic Charter, but that didn't stop Truman.
With France backed by the United States, Ho Chi Minh was forced to rely on military and foreign aide from the USSR and PRC, and it snowballed from there. The rest, as they say, is history.