I understand why people always say things like this. It's the not having a choice that ruins eternity. Fortunately it seems that such a fate is physically impossible in this reality. Even if you were made of the most durable possible material, you would still fundamentally be composed of baryonic matter, which means if you fell into a star, collided with a celestial object at relativistic speed, or fell into a black hole, you would surely die. There is always a way out for an enterprising immortal, and afterwards sweet nothing.
"Christianity again? After cowboys? You went all the way back around? Oh, god, why can't I die? This is the worst thing that's ever happened to anyone!"
Must not have actually saved the princess. Not sure what the correct course of action is, though. Certainly beat Bowser, but then I guess let her just be a princess/eventual queen? So don't marry her? Maybe that's where he messed up.
There's a whole-ass game about it.
... which is marked 18+ for some inscrutable reason. There's no smut and no gore. It's just gay as hell.
This is why Mario eventually turned into a cyborg and tried to wipe out the Mushroom Kingdom.