Beyond Dawlish

I'm looking for someone to pay someone to do my online class with some kind of guarantee. I'm investing money, and I want to be sure I'll get a good grade. Are there services that offer a money-back guarantee or promise a certain level of performance. I'm taking a chemistry course, and the exams are very challenging. I need someone who is confident in their ability to get me a passing grade. What are the terms and conditions of these guarantees. Are they realistic. I'm wary of services that make unrealistic promises. Any insights on the validity of these guarantees would be helpful.