You can rest in the promise that God gives you. You can remain steadfast in His word and it will not return void. People make promises and break them and break our hearts. You don’t have to worry about that with God. His word does not fail. In Romans it says, Therefore, the promise comes by faith, so that it may be by grace and may be guaranteed to all Abraham’s offspring—not only to those who are of the law but also to those who have the faith of Abraham. He is the father of us all. The key is faith, we have to trust that God has great things for us.
“Praise be to the LORD, who has given rest to his people Israel just as he promised. Not one word has failed of all the good promises he gave through his servant Moses.” 1 Kings 8:56