When Aldric said Issac was a righteous Fae, he did not mention the fact he was boring - and annoyingly strict. After Aldric left the dining hall after saying his piece, the fae forced her to finish her meal claiming it was the prince's order.
To be honest, Islinda had no appetite. Aldric's revelation that Valerie was responsible for the attack shook her to the core. She had no choice but to believe him but would not pass any judgment until she hears Valerie's side of the story.
If there's anything she's learned so far from being close to Aldric, he would manipulate everything in his favor. She would not blindly fall for his tricks, not when she has no idea of the full extent of his plans.
Hence she forced the food down her throat until she couldn't take anymore.
"I'm done." She pushed her plate back, looking at him from over her shoulder