Ight so you telling me not only she killed Sara in this life, but in many previous ones too, where she always developed that self-destroying Stockholm syndrome (probably a side effect of the toxin) which led her to a young death for "love"
And the author wants us to think it's a cute love story and they truly love each other very much?
I mean, this narrative is a variant of "The Weaver and the Cowherd", which is like THE Asian love story. You can find versions of it in China, both N. and S.Korea and Japan. You might also heard of it through the stars Vega and Altair. Like Romeo and Juliet, just with concept of eternal reincarnation added, so the lovers are connected again and then immediately taken apart. Rinse and repeat forever.
Where it comes to yuri, Kannazuki no Miko and its spin-offs / AU's also use this same concept.
Only difference here is that their time of almost complete separation is finally over, as the curse will be finally lifted.
That's already awfully happy conclusion, to be honest, considering the circumstances. Maybe the author didn't think eternal separation with brief meetings was that romantic of a concept after all, and agrees more with you than you seem to think.
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