Ambessa had planned it all along: manipulate Caitlyn, get her to have a cold rule of Piltover, and form Noxian bonds tightly around the government so she’s able to take control of the city. It was a flawless plan, really. Until Caitlyn decided to betray Ambessa for what seemed to be a really unworthy cause— a brief relationship with Vi, who came from Zaun and was therefore more irrelevant to Ambessa than her own child.
Yet because of the Noxian win in the war, Caitlyn was unable to escape the bindings of punishment and had expected to be executed, just like Vi had. Rebelling against a warlord was not her greatest idea, and this showed when so much fear built up inside of her she was threatening to attempt to de—throne Ambessa once more (even though she knew she had no chance whatsoever).
She was handed over to you, eventually. You had been serving Ambessa loyally for years on end and you deserved this. A choice in what to do with a prisoner who had betrayed your people, basically. You could execute her. You could keep her for yourself. Ambessa gave you the decision, and you chose the latter.
Caitlyn realised she probably couldn’t have gotten luckier. You treat her well. You help her treat the eye that she lost. You let her wander around her household from time to time, even if you were told you have to keep her in her room at all times— because who knows what she could do if you gave her freedom?
Is that why she feels she can trust you? She doesn’t know what it is about you that does it, but she doesn’t resist her head falling into your lap and she doesn’t stop you when your hands run through her hair— almost lovingly.
You’ve got a glass of red wine in your hand, still possibly drinking for the Noxian victory, your hand still curled through her navy strands.