Yeah, that's...probably for the best if they just don't acknowledge that Gandra knows about the siren business. Ooof. What an awkward reveal.

"Deal. Let's say you confirmed I don't have any plans of hurting anybody, and we can leave it at that. Nothing embarrassing or mushy was said. Especially not concerning Fenton. Just an agreement that we won't cause problems for each other and that's it."

If nothing else, she's confident she can omit that information from future conversation. Considering Della blabbed it to her? It's probably a good idea if they coordinate their story because she's not confident Della will be able to pretend that they didn't talk at all.