The E! series' preview clip shows Khloé and brother Rob Kardashian's surprised reaction to Kim's skin-baring dress.
"How much are you?" Khloé, 32, asks, leading Kim, 35, to admit that their neighbors looked at her as if they thought she were "hooker city." Adds Khloé, "They probably think Rob paid for you."
Talk then turns to Rob's recent spat with pregnant Blac Chyna, as the Arthur George sock designer acknowledges that he should sit down with his fiancée to clear the air. (Chyna is due in October with the pair's first child, and Us Weekly exclusively revealed in July that she is having a girl.)
"It takes either one person to man up — obviously that's gonna have to be me," Rob, 29, tells his siblings. "But at the same time, I'm not going to argue with the female. We had a good talk the other night, so we'll see."
Khloé reminds her brother that "arguments are normal," and that he needs to stay focused on what's best for his baby.
"I know Rob and Chyna have a long way to go, but I am really happy they are working things out," the Strong Looks Better Naked author tells the camera.
"Relationships are hard no matter what, and as long as Rob is trying and starts really engaging and communicating, that's all I could ask for," Khloé continues. "But he has to figure it out, and this is like baby steps to his life."
Watch the clip in the video above.
Keeping Up With the Kardashians airs on E! Sundays at 9 p.m. ET.
Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!