Karyn wasn't sure. At this point she didn't know what to believe, she knew what she used to know and feel about Jon, the way he used to be, but she didn't feel that way anymore. In fact, it was a testament to how highly she used to think of him that she was willing to even give him the benefit of the doubt now. Apparently she used to think of him what she now thought of Sarah. It occurred to her that this was because her feelings for Jon had simply been moved to Sarah, though it didn't occur to her that the Sarah in this world held the same personality now that the old Sarah had.
For now, though, with hopes that this Jon would be like the 'old' Jon, and with a backup plan that she might get him to drop his guard so she could take the stone from him. Frankly she was still thinking that Sarah was the only one she could truly trust.
"Yeah, sure, come on in."