It was alleged this week that Kendall and a friend left a New York restaurant without paying and when approached by a waitress in the street, Kendall, 18, chucked cash at her.
Kendall has already strongly denied that's what happened and yesterday her protective mum also waded in.
Speaking on E! News, the Kardashian-Jenner matriarch said: "Kendall is very serious about what people say and do and she considers her reputation everything.
"She feels like she did the most honest thing she could have done and was so nice."
A leaked letter from Kendall's lawyer has claimed the reality star's failure to pay her bill before leaving was an accident and as soon as she was approached in the street she immediately and politely handed over the money owed plus a tip.
Kendall, meanwhile, addressed the reports via Twitter this week, saying: "These rumours are ridiculous! I would never throw money in anyone's face or act that disrespectfully. I was raised better than that."
The waitress who made the allegations against Kendall has yet to srespond
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