On Restless, the inscription that Willow paints on Tara’s back is an invocation to Aphrodite, which is responded to by the goddess’s promise to make whoever the poet desires love her back in return. Part of the translation is:
For even if she flees, swiftly she will pursue;
And if she does not receive my gifts, she will give;
And if she does not love me, swiftly she will love,
Even against her will.
That indicates what happens on season 6, when Willow use magic to sustain her love with Tara.