Er, Wanda clearly
cast a spell on Jillian, and its
effects are visible when they next appear (note the "sparklies" around Jillian's head).
That said, it does seem that the
"underpinnings of this spell" that made Wanda so confident that it would hold (and so unwilling to objectively consider the risk that it wouldn't?) are based on Jillian's emotions. Note that she suggested that "both of us get out of here" before Wanda began the torture session or cast the spell. I think that gave Wanda confirmation that the emotional "underpinnings" were in place, and she could proceed with the spell. ("When Prisoner says 'the very easy way'? She gets 'the very hard way.'" was a literal, if oblique, statement of this.)
Also, considering that she's a rough and tough barbarian warlord, she didn't take much persuasion to go from smart-mouthing to "Yes, Mistress." (Admittedly, Wanda
wrote the book on that.
) My read is that this submissive aspect is what Jillian was referring to when she said
"I like it."
So, my read is that Jillian enjoyed being submissive to Wanda, and was emotionally bonded to her to the point of proposing that they run away together (to save Wanda from what seemed to be the imminent doom of her side). It is unclear whether this situation arose out of a pre-war relationship or out of Wanda cultivating a submissive streak/Stockholm Syndrome effect/whatever that emerged during early interrogation sessions. (I lean toward the latter, since it has at least some evidence in its favor: we
know that Jillian has been captured and "escaped" several times in the past).
The problem is that the relationship was highly exploitive on Wanda's part; she was using Jillian as a source of intel and (now) as a mole. My interpretation of Jillian's breakdowns (when
the session ended and when she found herself
unable to rationalize her way through the encounter with the wounded dwagons) is that she was reacting to being used and manipulated into betrayal. In the former case, obviously, the spell held and she (superficially) recovered. In the latter case, the spell broke -- Jillian is now aware of how Wanda used her and she is lashing out angrily (I think she'd be pleased if she could see how the sight of her "dolls" being broken affected Wanda). If she loved Wanda before, that just made her all the more enraged at having her feelings abused and used against her.
I think that Wanda did develop her own emotional bond to Jillian, without really acknowledging it (even, or perhaps especially, to herself), and that being so decisively rejected (and possibly believing that Jillian just got croaked, if she had already walked away in shock before Ansom arrived at the battle) is what caused her breakdown. Being totally wrong about something and having her plan fail as a result might be a contributing factor, but I can't believe that it's the primary one -- that happened earlier, when Ansom didn't show up for the original ambush, and there's no indication that she freaked out over that.