Today I attended a church service where the pastor preached on "believing for" things. He basically said that if you "believe" completely that God is gonna do something, then God will do it. I don't think I like that kind of theology. It takes the power out of God's hands and puts us in The Matrix. If I pray for something and God says "no" it's not because I didn't believe hard enough.
In Mark 9, Jesus cast out a demon which the disciples couldn't cast out. They definitely believed 100% that they would be able to because they had been doing it all day. Jesus told them "this kind can come out only by prayer and fasting". The disciples had lots of belief, but they still couldn't get what they wanted.
There's no formula for getting what you want from God all the time. Prayer with belief doesn't guarantee a yes or even a clear answer at all. Sometimes you just have to keep asking until you get it, like the woman in Matthew 15 who had to ask several times before her daughter was cured. I imagine, sometimes if you are asking for something God doesn't want to give, you may ask over and over forever and not get it: like me and 500 trillion dollars.
However, James 1 tells us that we shouldn't pray if we have doubt, because we won't get it. If that is the case, is it the same as doubt if we wonder: "will God say yes or no?" or "what if God says no?" or "God might say no, so I should prepare for that."? No.
Asking yourself those questions isn't doubt. The belief we should have is that if God wills something, then it will be done exactly as God wills it.
Like the guy in Matthew 8, who says "Lord, if you are willing, you can make me clean". God was willing even though the man gave him a choice, and Jesus cleared up his leprosy. Also, Shadrach, Meshach and Abednego, before they were thrown into the fire, said "... [God] will deliver us from your Majesty's hand, but even if He doesn't ...". They left room for God to have his will even if it wasn't theirs. They believed that God **could** save them and they believed that God would make the best decision even if it wasn't what they wanted. God saved them even though they might not have believed 100% that he was going to, because they believed that God could do it and that God loved them and cares for his servants and for the greatest good.
All that to say that if God doesn't answer your prayer, it's not necessarily because you didn't believe hard enough. Also, even if you believe 100%, it doesn't mean that you are going to get your way all the time.
We should let God know our prayers, but we should also tell God that his will should be done above ours.
"I listen to our blood run side by side."