Animation Source Forums

Why does Kovu save Kiara's life?

And why does Simba exile Kovu?

Because Kovu did it to get closer to Kiara so he could get closer to Simba so he could kill him.

Simba exiles kovu because of the ambush that happened by Zira and her sons/pride.

oh well after simba got ambushed by Kovu, Kovu said that he didn't have any idea.

He wasn't fully aware of what Zira was doing.

whitewolf17 i thought he did know what she was up to a little.

Yes,Kovu did know what Zira was up to a little bit.

Kovu:But I don't want.....(To be a king)

Here's a quote from wikipedia that summarises the ambush:

Kovu eventually resolves to confess his true intentions to Kiara, but before he can do so Simba takes him aside for a private conversation. The two walk into the area that had been burned in the earlier bushfire, and Simba tells Kovu the true story of Scar. Kovu finally realizes he has been lied to, but Simba reassures him that, like the green roots springing through the ash, what is 'left behind can grow better than the generation before – if given the chance'. However, Zira decides to take matters into her own hands and organizes an ambush. The Outlanders chase Simba into a gorge, where he begins to scale a wall of logs to escape. Nuka, in an attempt to prove himself, tries to follow, but slips and is crushed. Kovu, who had watched the scene from above, tries to dig him out, but is shoved roughly aside by his mother. Zira lifts up a log to see her eldest son barely alive. She tenderly cradles his face as he apologizes for failing her before dying. Zira blames Nuka's death on Kovu and slashes him across the face, scarring Kovu in an identical manner to Scar. Kovu defies his mother for the first time and runs back to the Pride Lands. Zira tells the other Outlanders that Simba has turned Kovu against them and declares war.

I nevered really thought about it that way but i've only watched it maybe five times and nevered really paid attention. But thanks anyways.