The last two sentences carried an implicit warning.
Everett Jones hadn't expected Amelia Clarke's opposition to be so resolute, he persuaded her, "Making Mason Carter the ambassador would definitely not be without its perks, and if he really can garner widespread societal attention, Mrs. Moreland, you too will benefit greatly."
That was a temptation.
Once a person becomes famous, by whatever means, what follows is all sorts of benefits.
Amelia Clarke remained unmoved, saying, "Mr. Jones, I respect Mason. When Mason wanted to perform in the play, I did not stop him. I also respect and trust you, that's why I was at ease leaving Mason in your care. I hope you will not disappoint me. I still have some matters to attend to, so I won't chat any longer with Mr. Jones. If there is anything in the future, I hope you can tell me in a timely manner."
After hanging up the phone once again, Amelia Clarke stared through the windshield at the morning streets of Capital City, somewhat dazed.