Jungkook is getting married soon, getting married to a guy he doesn't love. Because he knows his heart will always belong to Taehyung and only Taehyung.
"Tae, I don't want to marry him. I can't love him. Please run away with me." He offers on his wedding day but Taehyung only smiles.
"Jungkook-ah, if this will make things easier for you, I don't care what happens to me."
"No, Taehyung, I-"
"Just promise me you won't love him as much as you loved me."
"I-I... I promise." Before Taehyung leaves, Jungkook holds his hand tight, trying to engrave Taehyung's warmth into his, because he knows he can't hold him ever again. "Promise me we'll be together in our next lives?"
Taehyung kisses his forehead and he cries, "I promise."
Jungkook cries during the exchanging of vows because he realizes their promises will eternally be more valuable than the wedding vows he swore today.