That is the opening of Proposal Daisakusen .

Unlike the cool, perfect male leads found in many K-Dramas, Kenzo is flawed. He makes mistakes, he gets jealous, and he often trips over his own feet. This makes his journey incredibly relatable. You root for him not because he is perfect, but because his regret is so palpable.

: Netflix also hosts this unrelated but similarly titled Japanese series .

"Frustrated businessman Ken Iwata watches his childhood friend Rei marry another man. But when a mysterious fairy grants him the power to travel back in time to their high school days, Ken gets a second chance to win her heart—one classroom memory at a time."