Azula thinks killing Ursa will resolve the issue and repeatedly denies the truth that her mother loves her. After being tipped off by Ozai about a secret chamber, Azula finds an incriminating ...

and Ozai was ready to do it until his wife Ursa intervened. The conversation was not shown, but Ursa convinced her husband to instead let her poison and assassinate Azulon, all to protect Zuko's life.