How can you guarantee that this business plan will be profitable and especially with those specific numbers?
A business in only profitable if it brings in more money than the costs it faces. A plan is just a plan and nothing more. You can't guarantee that this business will be profitable unless you start the business yourself and then sell it when your balance sheet shows that it is indeed turning a profit. Until then it's just an idea. One that can fail just as easily and if not more than it will succeed.