The 31-year-old songstress Rihanna, real name Robyn Rihanna Fenty has reportedly become the world’s richest female musician, according to Forbes. Rihanna fortune adds up to $600 million, overtaken Madonna ($570 million), Céline Dion ($450 million) and Beyoncé ($400 million). Rihanna co-owns her ground-breaking cosmetics brand Fenty Beauty with LVMH, which is sold online and in …