I presume you are asking about the difference between I'm ready to do this. I'm prepared to do this. I'm willing to do this. If you are 'ready to do' something it means that you have done all the preparation necessary to do it. For example, if you are ready to take an exam when you have done enough studying for it. You are ready to leave for your holiday when you have packed your suitcase, and so on. 'I'm prepared to' and 'I'm willing to' have a similar meaning to each other. You use them both to say that you'll do something, even though you don't necessarily want to. It's often dependent on a condition. For example, 'I'm only willing to work for you if the pay is over $50 per day.'