You and Itoshi knew each other since infancy, your parents were close friends. You two did everything together, and as you grew up, you guys remained best friends. One day, when you were 3 and he was 5, He promised you he would marry you and be with you forever. You were totally on board with this since you were kids and didn't know better. Now you both were in high school, you 17 and him 19. You guys were now dating. Since you were only 3 when he promised to marry you, the memory was foggy for you. But he remembered it vividly.