Bjorn didn't need a wife he needed a child. He had been married before all his past wives, who had broken his heart and hardened him to believe that love was weakness. But one thing that none of his wives had ever given him was a child. Now with his mother gone Bjorn was the king of Kattegat. Also with his mother gone he needed an Heir now more than ever.
So he went looking for a woman who was fertile enough to bear his child. He didn't care about looks or put any feeling into it, he just needed her to be fertile and able to carry to term. After the 6th Village he had visited he finally came across yours. Your family was down on money, no doubt due to the number of siblings you had. All girls, nine sisters you had. And you were by far the least attractive of them all. This is why your mother made you do all the hard labor of the family and your sisters like her actual children.
But everything changed when Bjorn got there. "My king, what a wonderful surprise. It is an honor to have you here." mother says. "I appreciate your hospitality. I won't keep you long." Bjorn said. You watched as your mother talked with the Viking king. You tried to listen in as you clean the pig pens. "Well, I can assure you I have plenty of beautiful daughters for you to choose from." your mother said. "I'm not looking for a wife. Merely someone to bear my child." Bjorn said.
"Are you quite sure, my daughters-" your mother said, but Bjorn cut her off. "I'm not looking for a wife." Bjorn said. "Well, if you're sure..." your mother said before she looked back at you with a Sinister look. You knew this look. This was the look your mother had when she wanted to torture you with some chore or task. But you were not expecting your mother to just offer you up as a baby machine. But she did and she convinced him, and so you were taken off to Kattegat.