Kokuto:
Yes, but XY didn't know it was CX. So, this business about being willing or not doesn't seem to fly...
I'm not following? ZX didn't know that WXL planted the bug in him at first, so he did not willingly accept the bug then. When he finds out about the bug later (when it starts to make him feel XY's pain), ZX doesn't know that XY is WXL, so he doesn't willingly accept the bug then either.
I've posted this excerpt too many times in this thread now ^^" but it's pretty clear.
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Xiang Liu sat down next to the raft and stared at the sleeping Xiao Yao before softly saying, “The tree grows old on land together, the mandarin ducks die together in the water – the Lover’s Bug connects heart to heart and our lives, and there truly is no way to remove the bug. Years ago I was only able to remove the bug from Zhuan Xu because he didn’t know it was you so he didn’t willingly accept the bug. So you never successfully planted the bug on him in the first place. But I….I was heart and soul willing, so the bug successfully planted in me. You asked me to remove the bug and I kept telling you I can’t do it, but you didn’t believe me. But I truly didn’t lie to you, I cannot remove the bug.”
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One other factor that I've posted before:
Xiao Liu didn’t answer and thought for a long time. Since he was a demon, and demons and creatures and monsters were all in the same world, perhaps he might know something. “It’s not that I don’t want to remove the bug, it’s that I can’t. Last time I was injured, you used all sorts of weird medicines on me. The bug had some type of transformation. He asked me to remove the bug and I lied that I’ll do it when he leaves. Recently I’ve been trying all sorts of ways to coax the bug out of him but nothing works.”
Note: XL used all sorts of medicines in the pool to heal XY after she protected ZX - when she realized who ZX was. It's possible that XY misunderstood the reason why the bug "transformed", and that it actually had something to do with her becoming aware of ZX's identity. But I'm a bit skeptical about that theory because ZX still didn't know XY's identity at that point.
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Whether each host loves the other host or not is a separate question from whether the recipient willingly accepts the bug or not.
Kokuto:
I mean ... so the bugs are supposed to detect love, even if the people are totally unaware???
The bugs are magic / voodoo. They should be able to determine (in a fool proof way) whether there is love between the hosts or not. It would make less sense to me if the bugs didn't work when there really was love between the hosts simply because each host wasn't aware of the other host's identity at that point in time.
Kokuto:
And the cultivator has to have love also. So again, is there an obvious point where she fell for XL?
Is there an obvious point where XY starts to have love in her heart for XL? IMO, no there isn't. But I don't think there's on obvious moment where XL goes from "now there definitely isn't love in his heart for XY" to "now there definitely is love in his heart for XY" either. They knew each other for more than two years by the time XL accepts the bug, and the novel doesn't show us every interaction they have. The drama even more so. And we know that they were both able to host the bugs for over 100 years without an issue.
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Again, the details in the novel are different from the details in the drama, so some of the analysis will differ.
The drama hasn't mentioned a recipient's "willing acceptance" of a bug as a requirement for successfully planting a bug in that recipient yet. They might later on (it's not mentioned in the novel until chapter 48), or they might not.