A smug smile appeared on her step sister's lips when she finally revealed she was actually pregnant with her mate's child. Her father's futile attempt to apologize, for ignoring her all this time, because he had his own reasons and asked her to understand. A plea of forgiveness from her mate as he begged her not to reject him, claiming it was just a stupid mistake that he shouldn't have made. And to top it off, a cursed alpha from the north, to whom her step sister was actually promised, is here to collect his debt, so she has to take her place as the sacrifice now. Darn!
It is a good start of the story, but I do have some things to say about the writing. The dialogue is absolutely fine, given the fact that it's written Japanese-style, but you should try to avoid repeating the word "said" after every dialogue. Try to find some replacements for "he said/she said" or develop a bit more the idea, because the repetition can be distracting. I would also like to have more insight into the protagonist's mind and his feelings. Good job though! Keep it up!