This Time I Will Definitely Be Happy! manga summary:

“Wait for me, Louisa.” Those were the words that the hero, Graham, said to me before he set off to defeat the demon king. Graham who is both my childhood friend and lover. But, I have no intentions of waiting. In fact, I have the memories of my past three lives, and in all past three lives, I have been the hero’s childhood friend and lover. However, all past three heroes always found other women and never came back to me! That’s why I will no longer waste my time waiting for the hero to come back, this time I will definitely be happy!