Kim Kardashian appears on Wednesday’s “Tonight Show,” talking with host Jay Lenoabout everything from her 50-pound weight gain (and loss) to her plans for wedded bliss with Kanye West and baby North.

Kardashian says her recent sexy swimsuit selfie was her “big middle finger to the world on everyone that called me fat” during her pregnancy.

“It really hurt my soul,” the new mom says of the near-constant body criticism she received.  “It changed how I am in the public a little bit. I would go out and there would just be photos of me anytime I was hungry… and these stories where I was like200 pounds.”

Looking back, Kardashian says “it was the greatest challenge of my life to have gained 50 pounds” and to deal with the public’s cruelty to boot.

Even though she’s now lost all the weight, the reality star says the nastiness she faced has made her want to “live more of a private life.”

“Why would I subject myself to so much negativity? Especially now that I have a daughter. I just don’t need that energy. I rather be in a happy place, when I’m home,” explains Kardashian.

Now engaged after the “most magical night” of her life — Kardashian says West “did really good” with her massive 15-carat diamond ring — the bride-to-be is looking forward to her wedding.

“He definitely knows what he wants, and I want him to have whatever he wants,” says Kardashian, noting that the pair will likely settle on specific plans for a summer wedding after the rapper completes his “Yeezus” concert tour.

Kardashian confirms stepdad Bruce Jenner will walk her down the aisle, and that she’ll probably take West’s surname.

“My daughter has the last name West and we’re a family,” she says. ”So I want it to definitely be West.”

And how is little Nori doing these days?

“She’s the sweetest little girl. She never cries. She’s a perfect little angel,” says the proud mother.

Adds the star, ”I hope she grows up to be  smart and opinionated like her dad.”

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