Among them is a note Taylor sent to her first fiancé when she was 17 years old.
"I've never known this kind of love before - it's so perfect and complete - and mature," Taylor wrote to William Pawley on May 6, 1949. "I've never loved anyone in my life before one third as much as I love you - and I never will (well, as far as that goes - I'll never love anyone else - period)."
Taylor, who died at age 79, wrote more than 60 of the letters to Pawley, then a 22-year-old son of a former ambassador to Brazil.
They will be auctioned in May by RR Auctions of Amherst, N.H. It bought the letters two years ago from Pawley, who lives in Florida.
The collection of letters was valued at $25,000 before Taylor's death, but could now fetch three times that amount.
If you'd like to bid on Taylor's love letters, click here.
The Associated Press contributed to this report.