The mark of true faith is that someone takes God at His Word and believes what the Bible says.
To expect God to do what He has promised us, that’s never presumption. That’s faith. And you should take what He has said in the Bible and you should memorize it, you should know it, you should plead it, and give God no rest until He does what He promises to do. Live your life on what God has said in the Bible. Rest in these promises.