You can't believe anything unless you have the desire to believe it.
(Leaving aside all other contextualizing topics and adhering only to the statement quoted above):
"You can't believe anything unless you have the desire to believe it."
Is it permissible for me to extract this from the personal "you" and use the less particular "one" instead?
I'll address the statement as if that's okay.
You .. "One can't believe anything unless one has the desire to believe it."
Is this what you believe, RE?
Leaving aside whether or not I believe that you believe this statement, I must insist that ...
I don't believe this.
There are a good many things I'd like not to believe which I do believe. And the corollary (or companion, perhaps) of this belief of mine about my own believing is also true.:
There are things I'd like to believe which I cannot.
I have other beliefs about my own beliefs and the beliefs of at least a good many other people.
For example, I believe that desiring (or wishing) -- however intensely -- to believe in something is not anywhere near sufficient means to adopt a belief. And so on..., e.g., I believe wishing to believe X does not exist has no impact or influence on the fact as to whether X exists.
People believe in something when the evidence to them is sufficient for them to believe, provided that they examine and understand that evidence. The belief can then be altered only with new evidence and understanding -- not by force of will.
These statements about the beliefs of others are relevant in the case where the person in question has normal reasoning faculties and is not seriously mentally ill.
No matter how much effort I put into it, I cannot persuade myself to believe that a rock is a puff of air or that a circle is a square.