It's Complicated

Graveyard Scene in Winter Solider:

"Be careful Steve." Natasha said as she looked over at Steve on last time before turning around. Finding a new cover was hard for her this time, she had made an unexpected connection with him, and her leaving meant she'd probably never see him again.
Steve stared at her as she drew farther and farther from his view. He questioned why she was really leaving because in all reality he wanted her to stay. She was one of the few people he trusted, and after of all that had just happened, he wanted someone he could trust by his side.