I never said that the transition would be immediately for boyfriend and girlfriend and I surely dont want that for their relationship at the present moment of the story. However, I think that FWB is a step forward at this time and, if well executed, could lead to feelings of advancing further in the future. She isnt good at dealing with emotions, so she will keep the MC close to her pretending that is just sex and waiting for the moment when she is finally ready to pass that final hurdle.
If you notice, there are very few moments with Sage other than the Chad problems, the guitar lessons and the HOTs movie night/episode 4 and if im not mistaken, she has the lowest renders out of all the LIs and because of that she is the LI we know less things about (We know more the Sage Sex Goddess than Sage the Real Person)
I was also thinking that maybe the choice to take care of Sage in ep6 along with the her break up, might bring an opening to get people on her path again if they refused her before (Since we are only in ep6 and it would be dumb of DPC to lock a Sage ending in ep 2, but we never know with DPC
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)