Many of the letters will be published in a new book "Furious Love: Elizabeth Taylor, Richard Burton, and the Marriage of the Century" and are the focus of a July cover story in Vanity Fair magazine.
"Richard was magnificent in every sense of the word," Taylor told the book's authors, Sam Kashner and Nancy Schoenberger. "From those first moments in Rome we were always madly and powerfully in love."
Their romance sparked a scandal when it started on set, because the two were married to others at the time. The Vatican went so far as to publicly condemn it.
Burton addressed Taylor by the nicknames "Twit Twaddle" and "My Lumps" in the letters, which show that the Welsh actor remained in love with Taylor long after their second divorce in 1976.
Just before dying of a brain hemorrhage in 1984, Burton wrote to Taylor, saying that he wanted to come home to her, she told Vanity Fair.
But Taylor will keep that final love letter private, stored in her bedside drawer for only her famous violet eyes.
Reuters contributed to this report.