As soon as I saw The Offering, and heard that Justina had somehow miraculously been spared for years, I knew the game was rigged. I also figured she would swap herself for the other girl, given her sense of guilt.
The big question is, what is the true nature of La Ofrenda: there was some vague mention made of the girls being sent off to be married, but not to whom. My suspicion is they are "married" to a walker in some sort of attempt to appease the gods/ keep the walkers at bay situation. IOW, offered up to the walkers as a sacrifice. This would be in line with the sacrifice of virgins to the dragon in 1981's Dragonslayer, and how the names of some girls were kept off the list. [size=78%]https://en.wikipedia.org/wiki/Dragonslayer_(1981_film)[/size]
Aargh, that is horrible! This hadn't occurred to me. I hope it isn't true. I figured that the girls were being married of to older men since the "King" had a young wife. The wife did tell her lover that she found out where she was from talking to one of the girls from her town and she made it seem like the girls were okay. It could be that she lied, but I don't see how she could be so tolerate of her husband if he was sacrificing young girls. Unless, she doesn't know the truth. She might think that the girls have gone to other villages, but they really are killed instead.