In Xenocide, when Olhado says that when he and Ender are alone, he calls him Papa and Ender calls him son.
"Salaam."
In Shadow of the Giant, when Petra rereads Bean's note that Peter had read to her earlier, she realizes that the "I love you" at the beginning wasn't in the note; while the note of course said it implicitly throughout the whole thing, the "I love you" was from Peter.
When Ender gets into the simulator after being told that he'll be getting living subordinates... and finding out it's the children from the Battle Room, some of whom he considers friends.
Everything after the final battle in Ender's Game.
