Izumo was the only one to not care about the fact that Rin's the son of Satan. Rin was touched. Izumo was not.
Pretty much ALL Chapter 11 and 12. Until Amaimon appears.
On a mission in an amusement park, Shiemi wishes that she could come again when they're not on a mission. Rin tells her that next time he'll go with her and Shiemi agrees.
When Rin is suffering from crippling self-doubt expressing itself in rage in Chapter 26, he receives a Cooldown Hug from Shiemi, who hugs him despite Rin being on fire at the moment, proving her trust for him and renewing his hope.
Fujimoto's contingency should he die and Blackie find out - the wine they became friends over years ago.
Episode 19 is this for everyone.
In Chapter 32, while Shiemi tries to save her, Izumo yells that she hates Shiemi. Shiemi's reply is that she still likes Izumo and thinks of her as a friend even if she hates her.