She clearly stated that she had trust issues. When she spoke to Diandra earlier regarding Gautam and Diandra's relationship, she said...It is tough to judge someone's nature and intentions in this game show (Paraphrasing). With Diandra's loyalties being suddenly shifted from Upen to Gautam and her new found love for Gautam, she was confused...and finally went with her gut feeling.
I think she voiced her trust issues, when she asked Diandra casually if she's doing it for the game...and brushed it off lightly to avoid crossing any line.
This show is conveniently edited to make it under the specified time limit and to make it more dramatic. Precap only showed Karishma asking, kya apna naam lesakte hain...actual show showed many doing the same. The creative team are just banking on her selfish/self centered stance...which is not a bad thing at all. 😊