To answer this question, think about what these things tend to indicate about the mindset of the American (I assume this question is about the United States) public. If many people are willing to volunteer to join the military, does that mean that they support the war or oppose it? If people are willing to spend their money on war bonds, does it mean that they are in favor of the war or against it? If people are willing to go along with regulations that cut down on their personal freedom, are they most likely feeling positive about the war effort or negative? I imagine that you would say that all of these things show that Americans had positive attitudes about the need to fight World War II.
There are at least two reasons why Americans might have felt this way. First, they might have felt (particularly early on) that they needed to support the war so that the US did not lose. They might have feared that the US homeland could actually be attacked. These fears would have led them to support the war effort. Second, they might have felt that the war was a just war being waged for an important cause. They might have felt that the Nazis and the Japanese imperialists were both dangers to world security. They might have supported the war because they wanted to keep the world safe from these malign forces.
Whichever of these is true, it is clear that Americans were very supportive of the war effort in WWII. We can draw this conclusion in part from the number of people who signed up for the military, the amount of money spent on war bonds, and the general acceptance of the need for the special regulations imposed during the war.