Socialite Rebecca Grossman wept as she found out her fate on Monday for killing two young brothers in a September 2020 hit and run. Grossman, 60, was sentenced to 15 years to life after she was found guilty of two counts of second-degree murder, two counts of vehicular manslaughter with gross negligence and one count of hit-and-run driving resulting in death stemming from a crash that killed Mark, 11, and Jacob Iskander, 8, in a Westlake Village crosswalk,RadarOnline.com has learned. She was also ordered to pay $47,000 in restitution. Grossman struck the boys while speeding behind a car driven…