I once read a manga where a guy was sent as the bride of the mountain god (or a siilar entity) because there were no girls old enough and none of the brides ever returned. After meeting the god he finds out he actually helped the bride reach a new village where they were living happily. The village was sendong brides because they believed that this way their harvest would be good, otherwise there would be a plague of sorts. Please I want to re read this but I can't find it
I think it's this one:
https://www.mangago.me/read-manga/aijitsu_to_hanayome/
Bride of Ignat is really good too though. Highly recommend reading that one.
Here's a similar oneshot if you end up wanting more:
https://www.mangago.me/read-manga/mauri_to_ryuu/
Got too frustrated and couldn't finish it. I know it was supposed to be very cliché but considering she kinda knew the plot I was so frustrated she didn't make any connection between anything that was going on and the plot that she knew, even if she didn't really read the novel. She was basically floating through for most of the story without a care in the world. "Oh he's kind to me so he can't be a bad person/do anything bad" Girllll, be so fr. I hope in the last 5 chapters she kinda redeems herself but I won't verify ahaaha