She's getting sidetracked, here. Probably because Isabella is being her host and incredibly generous to a stranger without - apparently, this part itself is bizarre - any expectation that Thellim will be able to parlay her knowledge into trillionaire status and repay her - and Thellim isn't sure if that support gets shut off if she says the wrong thing - which means that she has a lot of things she wants to say back to Isabella on certain subjects, and has been suppressing herself from saying, because it may not be safe.
Thellim acknowledges this feeling; tells the feeling that it will have a chance to speak again later, when she understands her relationship with Isabella more solidly; and turns her attention back to analyzing Earth.