Watch Sweetheart (2021) HD Full Movie Free on SolarMovie. Watch Sweetheart (2021) online free. A socially awkward, environmentally conscious teenager named AJ is dragged to a coastal holiday park...A socially awkward, environmentally conscious teenager named AJ is dragged to a coastal holiday park by her painfully 'normal' family, where she becomes unexpectedly captivated by a chlorine smelling, sun-loving lifeguard named Isla.