Responses
She actually says that his smile lights up her world after they are reunited. So I don’t think he makes her that unhappy. I think the ending is so questionable because they didn’t take their time to highlight every detail shown in the novel for everything to make completely sense and be less vague (●'◡'●)ﾉ
So she went with him because if she didn't, she would be killed (she thinks). Seeing as we don't get to see anything after that I'll just assume she lives an unhappy life in fear of being killed by this crazy Duke who is obsessed with her LOL ╮(￣▽￣)╭