Wannetta

I just watched the movie and I do not understand why Wannetta turned against her people and went on Matt's side? Remember she said until she saw Matt, she only saw a white person once in her life.I know she bonded with the baby when she nursed it, and they tribe threw her out when she did not slow down the horses. But what was her motivation for not obeying orders? Then she threatened to burn the sacred ground down unless Matt and the baby were released. You would think she followed their religion? I wonder if she was treated badly by her people? Interesting question.