As a Boy, I Refuse to Conquest Beautiful Girls

Su Ningyun confessed to her childhood friend, only to be rejected and then killed by her teacher, who had been hiding her identity as an assassin. When she opens her eyes, she has somehow gone back three years and become her childhood friend himself? And her childhood friend is a high-ranking god of death? She assumes their souls have switched, but on the very first day after she transmigrates, her original body is cremated, and her childhood friend's soul vanishes without a trace. Could she really have to conquer 100 beautiful girls using his body to return to normal? No way! Isn't this just one giant field of grass? [Gender-Bender Harem, No BL or Bromance]