whatever you have done will return to you tenfold

We are told, constantly, that she keeps people at bay. We see her do this. But we also see that, when push comes to shove, she is desperate for connection.

Not to say that what she has with her Foxes and with Stix and even with her father isn't a deep connection — she is simply not letting herself rely on them in any way that isn't strictly practical and formally (socially) determined. Usually.

At her breaking point, though?

In Windwitch it is Stix who makes the 'first move', as it were, but she is encouraged by the temporary absence of Vivia's many masks.

In Bloodwitch, Vivia — whom we at this point know to be capital A avoidant, capital C cagey — outright begs her to call her by name. You could argue that this is too little, too late, that, after ≈ten years of desperately clawing at Viva's walls, Stix is entitled to some of her own. And her intentions are noble; she doesn't want Vivia to have any more problems to deal with. (She wants Vivia to know more than anything) (Vivia's wellbeing comes before her own).

Is this the exact same thing Vivia is doing? Probably not. Vivia keeps away from all, for fear that she might be hurt, if only indirectly, through not being wanted or respected as she is. Stix keeps away primarily from Vivia (though she tells no-one about the voices), for fear that she might make things more difficult for her.

There is a bond of unbreakable trust between them (Stix abandons her post and sends a message; Vivia evacuates an entire city) but still they are catastrophically bad at reading each other. In a way it's just bad fortune, that Vivia should need Stix most when Stix cannot in good conscience be only her Threadsister.

But Stix is also taking Vivia's distance for granted. Not entirely, perhaps not consciously, yet she phrases it as earning Vivia's true face, as Vaness breaking her walls down, when this is not something that has ever depended on anyone other than Vivia. Yes, Stix and Vaness and any other person could make it easier or more difficult; ultimately it is still Vivia's psyche, Vivia's work to do.

So we come to Witchlight, where Vivia understands herself, finally, but cannot possibly understand Stix, who, at this point, only half-understands her Paladin soul — and to Stix Vivia is still unknowable, even as she finally shows her true face without any reservations. A desperate final gambit that fails.