(CNN) -- Letters by a teenage Jacqueline Bouvier Kennedy Onassis to her Harvard boyfriend in the late 1940s show the future first lady writing about adolescent love, kissing and her loathing of attending a finishing school.
The 22 letters and a printed telegram are being auctioned by Christie's, which estimates the value between $25,000 and $35,000. The auction house describes the writings as "the earliest Jackie Kennedy letters," displaying "a funny, spirited, at times cynical young woman, but one with great intelligence and a strong will of her own."
On October 10, 1946, the 17-year-old Miss Bouvier reveals her "cooling enthusiasm" in a letter to Harvard boyfriend R. Beverley Corbin Jr., "who seems to have been badly hurt when Jackie refused to kiss him during one visit," according to Christie's.
Corbin was 21 at the time.
"I do love you though -- and can love you without kissing you every time I see you and I hope you understand that," she declares.
Then, on January 20, 1947, she writes to him about her definition of true love.
"I've always thought of being in love as being willing to do anything for the other person -- starve to buy them bread and not mind living in Siberia with them -- and I've always thought that every minute away from them would be hell -- so looking at it that (way) I guess I'm not in love with you," Onassis writes.
Her last letter to him is undated, and it announces her engagement to John Husted.
"What I hope for you," she writes Corbin, "is for the same thing to happen as quickly and as surely as it did with me. It will when you least expect it."
But that ill-fated engagement to Husted lasted only a few months in 1951, according to Christie's.
Onassis died in 1994 in New York as one of the world's most famous women. She was 64. In an extraordinary life marked by staggering tragedy, she was the widowed first lady of assassinated President John F. Kennedy, slain in 1963, and became a widow again, of Greek shipping magnate Aristotle Onassis, who died in 1975.
Corbin died in 2004 at age 79, according to the Social Security Death Index.
The 75 pages of letters were written between 1945 and 1951 on personal stationery and the letterhead of Miss Porter's School, but in the letters, Onassis calls Porter's finishing school "prison."
"If school days are the happiest of your life, I'm hanging myself with my skip-rope tonight," the teenage Onassis writes to her boyfriend.
In another letter, she pens of an upcoming Christmas break, when "I can commute happily back and forth between my doting parents until they both get sick of me."
In an October 3, 1946, letter, she jokes about her schooling.
"I'm never going to send my children to boarding school," she writes. "The boys can go to P.S. 148 with gangsters, and then go to Columbia & the girls can go to Hunter College and they'll all be morons but at least they wont have to tear around and get their teeth knocked out playing hockey every day. ... Can you think of anything worse than living in a small town like this all your life and competing to see which housewife could bake the best cake?"
The finishing school was in Farmington, Connecticut, a town where Corbin had resided at one time, a Christie's spokeswoman said.
Onassis displays a mischievous side in a February 12, 1947, letter in which she tells Corbin to smuggle in cigarettes, chocolate "and a hip flask to shock Mrs. J."
Many of the letters begin with "Dearest Bev" or "Buddy darling," and one envelope, sent via "air mail" with three 3-cent stamps, is addressed to "Mr. R. Beverley Corbin Jr." of "The Owl Club" at Harvard University.
The auction house is also selling an undated black-and-white photograph of Onassis and Corbin along with another couple.
The auction is set for May 19.
CNN's Amy Roberts contributed to this report.