Ore to Kanojo no Pandora Box

Synopsis

Our protagonist, who goes almost unnamed, except when he's called "Ka-bou" by his childhood friend, finally meets the girl of his dreams, Kanda Asuka, and confesses to her the very next moment. Oddly enough, she warns him that nothing but despair will fall upon him, but he doesn't care about this fact. Amazed by the protagonist's confidence, Asuka accepts his confession, but under one condition: To change the inevitable future that she's able to foretell. With rumors that she is the Lapis Witch, Asuka has the Pandora Box ability to foretell the dark future. To change the future, will our protagonist be able to accomplish this tall hurdle? Will he even take a step closer to finding romance with his new "girlfriend"? (Source: MangaHelpers)