In Soviet times there was one of selected best American sci-fi short stories printed here and there, and I believe it was one of those.
I always keep forgetting an author and title, cause the phrase "Painful death is best gift" is just imprinted in me.
So, an astronaut from Earth is settling on some remote planet with seemingly totally human-like aborigines (with a very early, a tribal peasants stage of their civilization). He has no problems in communications, he even falls in love and is happily married to some woman from a good family.
Having much more knowledge - medicine, construction, etc - he helps people a lot. And people seems very kind, open, maybe even naïve. Kind of pastoral happiness. They love and even to a degree worship him. He loves his wife and them too.
But weird things creep in. Like one wood cutter is died after a very thorny tree fallen over him, he was crying in pain for an hour before passing away. And our guy finds that the tree was covertly half-cut in wrong direction, and the cuts were somewhat masked, so allegedly the woodcutter would casually start axing it without noticing and gets killed. He suspects a murder but can't believe some one of those so open and kind people could be so double faced and can't think how he can investigate it.
Another villager falls into a mountain stream when the bridge falls. Our guy jumps into the water and manages to both pull him out and survive. The villagers are not happy though, they see this action as something very indecent. Like we would watch some savage killing neighbor and cooking him just to meet us from work with a feast. He wished well, but he did it in despicably harmful and wrong way. Like this.
Suddenly one of the villagers notes that the bridge ropes were semi-cut again, so and strong wind blow or jump could make them give way and make the bridge fall. The mood changes, now everyone again worships our guy and despises the saved local, like he was a fraudster. Our guy still thinks about finding a mysterious killer but no one else seems to take it seriously.
The suspense grows thicker an in the end we have his wife prepping herself for a night. She thinks how her husband is doing so many decent things, that he is so brave and kind, that he is almost saint. But of course he is so good, that he keeps himself reserved and he underestimates his good deeds, and he must not hurry and defraud the fate by setting his own death, like those deplorables did (he even risked his life to prevent that pathetic unworthy man to perish mischefly, that is why he was cheered). And that is how real saints should go. And she a good loving wife would help him: when his amount of good deals would mountain big enough and if the fate would still be too slow then she would reach for the family treasure - and she looks in a secret suitcase section upon a dagger covered with some ominous poison - cause the only best gift to the noble people you love can be, one that commits eternal happiness, is a torturous death.
Now, after this spoiler, I never can remember neither the author nor the title.