You're absolutely right Jakob didn't (doesn't) deal in the ephemeral vagueries of love, but I thought we were talking about what Cherry is trying to get Aiken to do to Erin.
I was agreeing with you. Jakob doesn't cast love spells; Cherry is apparently trying to get Aiken to cast one. They're both forms of control but the effect is different. Anyone who believes that Erin loves Adrian (or that any of the women in Adrian's harem love him) should also believe that she will love Aiken if this spell is cast. It
is the same thing.
That said, we've only got Cherry's description of what's happening to go on. But then I suppose so does Aiken, and he's apparently the one working the magic. So I suppose it
is a love spell.
In 630 Jakob also tries to convince Erin of the truth of her own words: that she doesn't really love anyone. The intention is to weaken her belief that she loves Adrian. (Possibly that suggestion had some effect, since it was given while she was at least feeling the
influence of the watch.) I wonder whether the intention here is bring Erin under Cherry's control (and thus Jakob's) or whether it's simply to separate her from Adrian. It's not clear how having her in thrall to Aiken gifts her to Cherry, although Aiken at this point appears the weaker of the two (indeed, the weakest of the three).