"This," she said, waving a hand to indicate the two of them. "I don't do the touchy feely crap very well." She kept running out on him. It was becoming a theme for them, and she knew if she kept running, he wouldn't always be there when she decided to come crawling back. She'd been lucky so far. He hadn't had anyone else to go to. But that could change, all too quickly. She needed to get her act together, stop being so ass backwards about things, and own up to how she felt about him.
Except she couldn't.
As they entered the lobby of the apartment complex she smiled softly, feeling the cool darkness slide over her. She thought of the first time she'd come here, so afraid for him. She hadn't known then the depth of her feelings for him. She'd only known that she cared about him, that he was important to her in a way no other being had been before, and that he needed help. She'd tried to rationalize it at first, claim that by staying close to him, being important to him, she kept herself safe. His presence had protected her from Crowley once, after all. But it wasn't true. She'd just wanted to see him, to be close to him. Now, she could be, and she kept running away. Clearly she was damaged goods, but there was nothing she could do about that now.
"Castiel," she started, trying to sound sober and serious, though she knew she would never make the promise she was about to give him if she'd been in her right state of mind. "I'm going to make you a promise. I'm not going to run out on you again. As long as you need me, I'm here." She could have elaborated, added qualifiers, left herself loop holes, but she didn't. She'd probably regret it later, but for the moment it felt good to say.