Why did Zira say that Kovu was in on the ambush?

[FriendlyHyena]

I'm curious what she hoped to get out of lying about Kovu being in on it. We know that Kovu was exiled because Zira had said he was part of it, but obviously Zira DIDN'T intend for Simba to get away alive from that.

So, I'm curious, what would it have mattered if she had said "We're here, no thanks to Kovu" and thus showing that Kovu HAD indeed double-crossed her. Actually, given how Zira had later told Vitani that if she wouldn't fight that she'd be killed too, I'm surprised that she didn't order her pride to off Kovu along with Simba, nor why she didn't try and kill Kovu after Simba got away and Nuka was killed.

Was she hoping that by trying to implicate Kovu in this, that he'd know that he couldn't go back even if Simba survived, and hoped that would motivate him to return to her side?

[TheLionPrince]

Great question! It was never hinted at all that an ambush attack by the Outsiders was ever planned. The plan was that Kovu would earn Kiara's trust and use her trust to get close to Simba and kill him.

It would be too easy to call it a plot hole, and it probably is, but Zira was most likely lying. In Zira's eyes, Simba and Kovu walking side-by-side would sealed the deal that the plan for Kovu to get close to Simba had indeed worked. So, implicating Kovu as an enemy agent all along would make Simba look like a naive fool for having ever trusted in him. After all, Zira did not intend for Simba to survive the ambush.

[SimbasGuard]

Zira painting Kovu as a traitor also set Simba against him. Thus making it impossible for Kovu to stand with Simba and fight The Outsiders (even though Kovu did try to fight The Outsiders).
Also causing Simba and Kovu emotional pain before she kills them would be like icing on a Cake for Zira. Not to mention a great way to honor Scar.
As for why Zira didn't kill Kovu after Nuka's impromptu funeral. She did try to use Kovu's guilt over Nuka's death to turn him back to the proverbial dark side as it were. Although Kovu was too smart to take the blame.
Zira implicating Kovu might have had a two fold purpose. Emotional torture on Simba and Kovu. Also as a contingency plan in case the plan failed. Kovu would not be able to go back to The Pride Lands and would not have been there to fight The Outsiders.

[MeerkatOnTheMoon]

A very thoughtful, interesting discussion. I still felt bad for Kovu over this - especially at a time when he really had a change of heart - and wish he went ahead and told Simba about what Zira had planned all along. Not One of Us is still hard for me to watch at times, mainly 'cause I have been accused of something I didn't do one time (it was a light situation and the other person was in a very bad mood but still) and only a couple people stood up for me. Great explanations above, and I agree that Zira painting Kovu as an enemy agent was an intent to make Simba regret accepting him into the pride and to cause emotional pain between both.