Have you even had times when you have wondered--is God even listening to my prayers? Does He even incline his ear to my requests and answered them?
That is a few questions. And the Bible infers the answer to the last two by what it does say.
I consider the Bible to be God's communication with us humans in the revealing of Himself. All through the first half of the Bible He reveals Himself as a person who hears prayer and answers prayer of those who are in a relationship with Him.
He gave a son to Hannah when she asked. He saved Lot form Sodom when Abraham asked Sodom to be spared if ten righteous people could be found. Only Lot was found.
He heard Jesus when Jesus prayed. He hears us also according to 1John 5:14. "And this is the confidence that we have toward Him, that if we ask anything according to His will He hears us.' (esv)
It is my contention that our asking is what is being referred to here as God's will.
this promise is only for Christians. I define a Christian as one who has a relationship with God through Jesus Christ. It is a family relationship.
As for belief, this is where faith steps in. For without faith it is impossible to please God. Faith says that God exists and is one who rewards those who are His.