In the case of a סוטה (wayward wife) we have an amazing and miraculous way to figure out if the woman is guilty or innocent. What's so special about the case of סוטה that we have a very special method to get a verdict, versus any other case where punishment is by death?
I understand that in the case of Sotah, there really is no way for anyone to have known (besides the guilty parties). But there are many other cases where it's also quite impossible for anyone to know (e.g. no witnesses by an intentional murder case). Why specifically sotah?