After the ships disappeared from sight, Nina backed from the cliff a couple steps before turning and making for the forest. When she reached the glade she often sat with Hiccup in, she slumped against a tree and tried to convince herself that her parents were going to be fine. She put her head in her hands and focused on her breathing in an attempt at calming her fears. Nothing worked.
Just when she felt like the world was closing in, she heard footsteps coming up the path. "Hey." She looked up and saw Hiccup standing there, goofy grin on his face. She turned her head away. "What's wrong, Nina?"
"It's nothing," she said shortly. "Aren't you going to abandon me and go off to fawn over Astrid some more? Seems to be your favorite pastime now."
He sat down beside her. "Nah, she's busy right now," he said. "Besides, we haven't hung out in a while." She didn't respond to him. He nudged her arm in an attempt to make her smile. When he realized she wasn't going to change her expression, he put an arm around her. "Your mom and dad will be fine, I promise, Nina."
"Why do people promise things they can't guarantee?" she asked in response.
"Huh?"
"Everyone makes promises they can't keep. No matter how many times Mom and Dad have tried to convince me that they'll be back and they'll be fine, I can't shake this feeling of overwhelming dread that something terrible's going to happen." Her shoulders began to heave and then she had her face pressed up against Hiccup's shoulder with his hand on the back of her head. "I'm scared they won't come back." Her voice was muffled by him, but he understood her.
"I'll be here for you, Nina. I promise," he said. "I know I can keep that. No matter what happens, you can count on me." She finally allowed her tears to fall and hugged him tightly, burying her face into his furry vest. He returned her embrace with a nice comforting squeeze of his own.