Originally Posted by Keyser Soze
Nah, I think Loki's love for Frigga was genuine. That was laced throughout the film. And I even recall reading the first draft script for the first movie way back, and there was a whole lot of stuff about how Loki was always estranged from Odin but had a close relationship with Frigga that didn't fully transfer into the eventual film, but which they seem to have carried over more here.
It definitely seemed genuine to me, in fact it was one of the more genuine and focused on aspects of Loki's character in the film. Especially in the scene they share together in the prison chamber... and it's further displayed in the scene between him and Thor straight after her death, with Loki laying on the ground looking fairly dishevelled and dejected.