Still, you're looking at something in isolation that was from some time ago at a point where Sage was just after some D to sate her lust, but things have moved beyond that and are likely to do so again in Ep 7.
When the MC calls Sage in Ep 4, his scene with her at both the Prep party and at the HOT house in Ep 5, and the hangout in Ep 6 are all clear indications that Sage is developing deeper feelings for the MC. In fact, Ep 5 makes it very explicit with this exchange:
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Just look at Sage's expression when the MC suggests them being a couple. If that isn't the look of someone who's falling for a guy then I don't know what else you could be looking for from her.