It took Cas a moment to respond. Even though she wasn't the Anna that he had fallen in love with here, she was still Anna. The fact that, in spite of her own history with him and the time she had come from, she had come here for him, meant more to him than he could really express. He let go of the tight hold he had on his emotions and let some of the pain and weariness he was feeling show.
"Thank you," he said softly, with a small smile. "That...it means a lot to me." He sighed. "I'm glad you weren't here," he admitted after a moment. "I'm not sure what I would have done if you had been here and something had happened to you. It was...a complete mess." There were no others words for it.