Answer: Lack of knowledge
Explanation: In my opinion, desperation = pain, and pain = experience. With experience, it's easier to point out and notice a fraud. With lack of knowledge, it's harder to be aware of one, because you don't actually know what it's like to come into contact with one, and experience is pretty much equivalent to knowledge. Without experience, you don't learn things, and you become less wise. Therefore experience = knowledge, and lack of knowledge makes people more vulnerable to a fraud. I know the answer to this question, because of experience with a fraud myself.