Diaval taking care of Aurora as she grows up, from rocking her to sleep to playing chase with her as a teenager. When she finally meets him as a human, it's clear how much he cares for her.
Aurora: I remember you! Pretty bird!
Diaval's sincere dedication to helping Maleficent. What starts off as an obligated pledge of allegiance eventually grows into a true friendship. The fact that they both get to live helps.
Best exemplified in the scene where they enter the castle. Diaval warns that they'll get themselves killed. Maleficent snaps that he's free not to come. Diaval grumbles about her constant rudeness - while following her in without a second's hesitation.
Aurora's genuine interest and lack of fear towards Maleficent also counts. Maleficent cuts a truly intimidating figure and Aurora is barely even phased. Her claiming that she always knew Maleficent was there helping her is extremely sweet.
Maleficent saving toddler Aurora from falling off a cliff. No matter how much she claims to hate the girl, even she can't let a child die. To cap it all off, Diaval gives her a look as if to say, "I saw that, you big softie," to which Maleficent snaps, "...What?"
As Maleficent is healing a damaged tree, a young Aurora fearlessly approaches the terrifying figure of the wicked fairy and greets her. Maleficent tells her to scat, but the little princess hugs her, ignoring by the fairy's insistence she doesn't like children. At her sweet demands of "Up, up!" Maleficent picks her up, and little girl proceeds to tug at the fairy's horns. It is adorable.
Made all the cuter by the fact that Li'l Aurora is played by Angelina Jolie's own youngest daughter—the only child performer who wasn't afraid of Jolie in the Maleficent costume and makeup.
Maleficent, despite her descent into a depression and covering the Moors in darkness, spends her time healing trees, just like when she was young and full of hope.
When Aurora goes to tell her "aunts" that she's leaving, the three of them immediately stop arguing and bring out a homemade—if badly baked—cake for her birthday. Even if they weren't the best caretakers she could have had, they clearly did try.
At the beginning of the movie, Maleficent frees Diaval from a trap/net, saving his life. At the end of the movie, he does the same—net included.
It's easy to overlook, seeing as how he became a bastard later on, but Stefan throwing away what was likely his most valuable possession just so he could shake a girl's hand. There's a reason it "moved her (Maleficent's) heart beyond words".
Just before the mud fight scene, a squat goblin-like fae, with his friends' encouragement, gives Aurora a flower. Brief, but absolutely precious!
The mud fight scene itself, especially since it's a nice breather from the overall dark tone the film has at that point. It also serves as a nice scene of Maleficent, Diaval, and Aurora spending time together.
In the novelization, Maleficent notices that Diaval visits Aurora every day (ending up basically raising her), and he defends her to Maleficent and tries to get her to come around. This◊ fan comic pretty much sums it up.
A Deleted Scene shows Diaval expressing concern that Maleficent hasn't revoked the curse yet. This is before even the cliff scene, and Diaval already loves Aurora! D'awww! (Not to mention that this is the first time he's called Maleficent out for where she's directing her revenge and not listening to him if it doesn't suit her.)
While their relationship appears to be platonic when Diaval is in human form, when he is in animal form Maleficent is more openly demonstrative towards him. She seems to almost always have him with her when presenting herself as ruler of the Moors, and strokes his bird form. When they fail to reach the castle in time to stop the curse, she sadly rests her head against his equine neck. Her denial that true love exists clearly upsets him. But at the same time she does seem to love him and just doesn't want to express it when he's human because of what Stefan did to her. When they crown Aurora, she has him at her side, in human form, like a consort (and as if they were Aurora's parents, which in a sense they were), both during the ceremony and later when watching it from the overlook. Plus her "happily ever after" is flying free with him.
Prince Phillip and Aurora's awkward first meeting is this, with their meeting feeling more natural than the original cartoon.
Maleficent growing to genuinely care for Aurora, which ultimately breaks the curse.
Aurora: Hello, Godmother.
Maleficent: Hello, Beastie.
Everything about the ending. First, there's the coronation, in which we see that the Moors have returned to their natural lovely state. The fairies are all cheering for a beaming Aurora, while Maleficent and Diaval watch, looking for all the world like proud parents. When Phillip shows up, Aurora just smiles at him and pulls him in for a dance, showing that she has no hard feelings about being kissed against her will. And finally, there's a Book Ends shot of Maleficent flying through the sky with Diaval at her side, smiling and laughing for the first time in sixteen years.
Related to the above scene, there's the brief moment where Balthazar, the leader of the Sentries, offers his hand to the newly crowned Aurora, which the latter accepts with a smile. Considering that the Sentries had at that point been portrayed as fierce warriors, it was a rather nice scene.
◊ fan comic pretty much sums it up.
