I really tried to bring Sif a little bit more vulnerability in this film. She has a very big soft spot for Thor. She’s very much in love with him and cares very much about his well-being, as well as her fellow Asgardians’ well-being. So knowing that he’s kind of in charge of that, she really appeals to his softer side and says, “Let me talk to you about this. I care about you, and I see that you’re very distracted and I want to help you focus again because we have a lot to do.” I’ve got to tell you she’d be an awesome girlfriend! I think they should probably take it there eventually. Sif kicks a lot of butt in this movie, but she also opens her heart a lot.
– Jamie Alexander interview to comicbook.com