Responses
He had no choice because she testified in front of the people that she knew what her family was doing, so he had no other choices except to punish her by death. If she had said that she was innocent then she could lived and was sent off to the monastery instead.
But if she had lived there would have been people that held on to resentment despite her not being entirely guilty, and maybe would have questioned his leadership and love for her, so her dying and being really bitchy strengthened his foothold and allowed him to crest what he has at present.
so why did he kill her again?..i mean not again but tell me again...? all the spoilers did enlighten me with her stupidity and his eternal love but ..so why kill her?