Heartwarming / Journey into Mystery (Immonen)

• #652: When Lady Gaea falls ill, Sif looks for advice from Jane Foster. They bond over cracking plant jokes at Thor's expense before Jane refers her to Tony Stark.
• Heimdall pleading with Sif to not enter the portal and Sif ultimately deciding to stay in #650. Given that the siblings have been nonstop fighting each other, both verbally and physically, throughout the first arc, it's as clear as day Heimdall does ultimately care about Sif.
• Journey Into Mystery #650: Sif engages in a snowball fight with some local kids and has a blast. One of the kids asks her if she's happy that she joined them.
  Young boy: Still happy you said yes?
  Sif: Never been happier.
• It's heartwarming to see Sif get along with Jane Foster and defer to her expertise, as Jane and Sif are both Thor's love interests.