I think it's impossible to believe simply by choosing to do so. In a certain way, you don't have a choice in the matter. (The christian explanation for it is that only god can change your heart.)
I mean, you can perhaps make yourself believe by way of self-hypnosis and auto-suggestion, which is probably what actually happens in churches - but if you were to do that consciously, you'd still have the problem that you would KNOW that it was yourself who made yourself believe.
I think there is a certain confusion in the whole concept of religious belief. There are certain experiences, like a perceived miracle, altered states of mind, maybe meditation, or awe-inspiring natural phenomena, which trigger spiritual states. And then afterwards, we attach explanations to that, and if the only available explanation at that time is religious, we stick with that. Add confirmation bias and group-trance, and you got yourself a cult.
But inside christianity, or any faith-based (revealed) religion, it's often seen the other way around: FIRST you believe, THEN god does something in your life. Only it's simply not true.
And that, IMO, is also why evangelisation doesn't work the way it's often expected to - by convincing people logically. (It's why Jehova's Witnesses seem to be in a stalemate - they rely on logic and reason to convince people, and they don't appeal enough to emotions.) Evangelisation really only works by creating that altered state that is inducive to spiritual experiences. That's why they always try to pray with people on the spot.
ETA: That first sentence up there originally read "I think it's impossible to believe against your own will. ", which does not make any sense at all and was just a mistake on my part.