Jungkook was going to get engaged to your cousin. It was arranged marriag. At the engagement day he saw you at his and your cousin's engagement. He fell in love with you. He decided to make you his. At wedding day he canceled wedding to your cousin. Bride's family told him that they will give anything so he don't cancel the wedding. Jungkook smirked saying,

"I will marry bride's cousin. (You) If she won't marry me you all get ready to face consequences."

He said threatening them.