The letters are written to the actress’ friend Sir Felix Alymer between 1951 and 1960, are up for sale with auction house Bonhams and are expected to fetch upwards of $5,600.
The ten letters are from a period described by the auction house as the most "dramatic decade of her life".
On her broken engagement with James Hanson:
"It is with a heavy heart I am writing to tell you James Hanson and I are no longer engaged," she writes. "I know there is little I need explain to you, a gentleman of this profession. For a year I thought it possible to make our combined lives and careers work out...It is all very unhappy-making but I am sure it is the only sensible decision.
On her wedding to Mel Ferrer:
"How dearly we would love you to be with us on our wedding day...We will have the car take you up to our mountain peak, Friday, for a gathering in our chalet of our nearest and dearest!...Saturday will be the wedding...We want to keep it a dark secret in order to have it without the 'press.'"
On the birth of her first child, son Sean Hepburn Ferrer, after suffering two miscarriages:
"Sean is truly a dream. I find it hard to believe he is really ours to keep. I long to show him to you. We all three send our love and kisses, Audrey."