"I wanted to believe you, Hunter, but I couldn't ignore the doubt lingering around my mind. I should've listened to my heart," Hera admitted more to herself, expressing again and again how much she regretted hurting him.
That day when Clara revealed how Hunter and his friends ill-treated her by doing awful things to her, Hera couldn't see past the unjust, tragic occurrence that she assumed Clara might have gone through. The genuine pain etched on Clara's face had manipulated and steered Hera's mind away from thinking sensibly.
She was confused, which led her to misjudge Hunter blindly.
Clara had successfully brainwashed Hera to believe in her concocted false story, and Hera never saw the hostility concealed behind her once best friend's pretend misery.