What Tara can’t make Willow understand is that magic, real magic, is about life and death, the natural cycles that make the world function. Willow wants to control it, re-make it in Willow pattern, but that was missing the point.

Until Willow sees, really sees, what she’s doing is wrong, there’ll be no hope for them. It pains Tara to feel this way, to love the woman so deeply, yet fear her too, but it’s down to her to be the one with the resolve, to make Willow see the harm in her actions.