In this world we find that it is getting harder to depend on what many people say. So many times we are "let down" time and time again because people area not "true" to their word.
But there is very good news - we will never be let down by God - Never, Ever, Ever! God says that His Word (The Bible) is truth. Not one Word of His will return unto Him void. When we speak the Words of the Bible (the promises) to Him - He will always act on our behalf. God even says that He is not man that He should lie, so He swears by His own name.
When I was first learning that I could depend on God to do what He said He would do - I was very excited. For almost 35 years as a Christian, I thought His Word was "hit and miss" depending on how God felt at the time and how good I had been. Bad meant that I might not receive and good meant I had a good chance to receive what I asked for. No confidence or faith there, right?
Read 1 John 5:14-15. It says this is the confidence (assurance) that we have in Him (God) that, if we ask any thing according to His will, He hears us: (His will IS His Word). And if we know that He hear us, whatsoever we ask, we know that we have the petitions that we desired of him.
So we know that when we ask God in faith for anything, we know we can believe (the very moment we pray) that we have received what we asked for in prayer. Now that's God for you - He doesn't keep you guessing, that's true confidence. Whew! I feel more confident already, don't you?