Romans 5:5

Paul has just built a sequence that most readers find suspicious. Suffering produces perseverance; perseverance, character; character, hope. It reads well until you have actually suffered, at which point the obvious objection appears: the sequence often fails. Plenty of suffering produces bitterness, not perseverance.

This verse is the answer, and it does not defend the chain by arguing about suffering. It changes the subject to the source.

Hope doesn't disappoint us — the verb is closer to put to shame. The picture is of someone who backed something publicly and was made to look foolish when it collapsed. That is the specific fear about hope: not that it hurts, but that it exposes you.

And the reason given is not that things will work out. It is that God's love has been poured out into our hearts. Past tense, already done. Hope is not underwritten by a forecast about the future; it is underwritten by something that has already been delivered.

Poured out is deliberately excessive — the word suggests overflow, more than the vessel needs. And the delivery mechanism is named: through the Holy Spirit who was given to us. The love is not being described as an idea Paul hopes they will accept. It has been put inside them by someone.