Money can’t buy you happiness, just ask Paris Hilton. The heiress, 39, opened up about her painful upbringing in a new documentary, This Is Paris, on YouTube. “I’ve been playing a character for so long that people would assume I was a dumb blonde,” she tells Life & Style. “But I’m not, and what I have went through [has made] me the strong woman I am today.” In the doc, which premiered on Sept. 14, Paris details the terrifying abuse she allegedly endured at Provo Canyon, a boarding school in Utah that she attended in the late ’90s. “Every day there was complete torture, being verbally, emotionally and physically abused,” the Simple Life star claims. “For so long I tried to erase those memories from my mind, but it was…