This year marks 100 years since the birth of Marilyn Monroe , the Hollywood star whose work, image, and life have fueled impassioned fascination and speculation long after her death. The Monroe centennial is being marked by a major show at London’s National Portrait Gallery in June, but not before artifacts related to the screen icon emerge on the block at Heritage Auctions and Julien’s Auctions . On June 1, Heritage is offering more than 80 items that offer an intimate, unfiltered window into Monroe’s inner life and relationships. At the center of the sale is a cache of letters, documents, drawings, and notes from the collection of Norman and Hedda Rosten , close friends of Monroe. They met through a mutual friend in 1955 and enjoyed a whirlwind seven years, spending time together on both sides of the Atlantic, exchanging letters about love and poetry, and even offering professional help, with Hedda briefly acting as Monroe’s assistant and secretary. Watercolor illustrations by Marilyn Monroe.…