It seems a strange question that anyone with hope/absolute certainty could doubt. Well, it does happen, doesn’t it?! But of course the critics are never far away with these and other questions.
Paul answers the question in 2 ways.
And hope does not put us to shame, because God’s love has been poured out into our hearts through the Holy Spirit, who has been given to us. You see, at just the right time, when we were still powerless, Christ died for the ungodly. Very rarely will anyone die for a righteous person, though for a good person someone might possibly dare to die. But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. (Romans 5 v 5-8)
There it is. We know our hope will not be disappointed because of God’s love for us; seen in the activity of the Holy Spirit and the cross of Christ.
See that word ‘poured’? I wonder what Paul must have been thinking when he used it. Was it the great outpouring of Pentecost? Though Paul wasn’t a receiver on that day he certainly knew the Holy Spirit filling his life post-conversion and so do we. The Holy Spirit in your life is constantly reminding you of God’s love for you. “You are a child of God”; “You belong to Him”; “You are under His gaze”; “He will bring you home”; and your responses are filled with even more hope, “It is well, with my soul”. That’s our answer. This hope will not be disappointed because we are reminded inwardly by the Holy Spirit of the love of God.
Some might say to us well all that is subjective.
So our proof of God’s love is the cross of Christ. To die for a loving person is one thing but to die for someone who is a sinner is another. He died for you and me whilst we were not worshipping Him and with our backs turned against Him.
Subjective and objective proof that God’s love means our hope for the future will not be disappointed.
But there’s more …