So I've been scourging through the Creation Kit and noticed that from the very beginning Serana has two sets of dialogue - normal and those that come only when she likes you. I've only been getting the first ones. For example, when you go to Volkihar for the first time she says:
"I know your friends would probably want to kill everything in here. I'm hoping you can show some more control than that. Once we're inside, just keep quiet for a bit. Let me take the lead."
That's the normal line you get. Pretty cold and all with no developer notes. But then there's this one:
"I just need to be alone. For a while. There's a lot of feelings wrapped up in this old place, and I don't think you're quite ready for them. So let me take the lead in there."
With the developer note:
like the early phase of a relationship where you don't want to show all your crazy to the other person yet
And when you respond to her innuendo later on during the Moth priest quest, you typically get this line:
Serana: "Turns out you don't learn much from just sleeping with something."
Player: "Are you saying you want to learn more about me?"
Serana: "Not at this rate, no."
But with high disposition you would get this line:
Player: "Are you saying you want to learn more about me?"
Serana: "I guess you'll never get to find out."
With the developer comment: this is flirty, not dismissive
So how do you gotta treat her to get these lines? I'm rather curious if it's even possible to get these lines so early on since I sure have never seen them in-game, even in some Lets Plays that I've watched. I went for all the positive lines ("Are you alright?" and such) but I still get the neutral responses.
Given that I plan on having Serana as a main follower for this playthrough I find myself obsessing over small details like these. I had to reload an earlier save and put my character on hold until I resolve this