Dakota talks a little bit about Kristen and their relationship in a new interview (I heart their friendship SO much)
Q: Kristen Stewart, who plays Bella in the Twilight films, has a reputation for being sullen. True?
A: Kristen has become one of my best friends (the two also appeared together in The Runaways), and she's one of the most fantastic, lovely people I know. She's one of the greatest friends you could have. Kristen's not sullen. She's just so passionate about what she does; she wants to give it her best all the time. She takes everything to heart, and she comes across as serious.
Source and for the rest of Dakota's interview Read more: HERE