The Time Traveler Wants Me to Be Her Fiancé

"Wait, in the future I'm the greatest psychic in the galaxy, a legendary powerhouse and guardian of the Earth Federation, and, on top of that, the galaxy's universally acknowledged harem king who sleeps around? And after meeting you, I made a promise to go with you to the last planet before the end of the galaxy, watch a star explode, and then get married?"

"That's right, more or less. You've always been my fiancé, darling."

"But... I'm a girl."

"Mm, you're a little cuter than before, and a little shorter. You're not as tall as you used to be, either, but it doesn't matter." The girl smiled. "I still love you, darling~"