Unquestionably, the death of the Evil Queen in The 10th Kingdom. Just hearing her call Virginia her little girl with her last breath is pretty heart-wrenching.
Just listening to Virginia baring her soul about being abandoned when she was seven. Particularly the lines: "I miss her. And I hate her! And I miss her! Just adding another bit from the same scene as above when Virginia recounts the feeling of being abandoned by her mother as "I was on a train and it crashed or something, and no one came and rescued me!"
Watch this scene while remembering how indifferent she acted back at Snow White's Cottage when Wolf was asking about her mother, and it's not hard to tell she was holding that entire rant back for a very, VERY long time.
The scene where Tony fell down in the mines was also tragic for Virginia. The poor guy suffered from a lot of bad luck and this could have resulted in his death.
The dream Virginia has in the swamp is a mix of this and very creepy- particularly the part where Virginia's mother is seen telling her a story and when Virginia screams, "Well, I'm glad you finally have a son now, AT LEAST THAT SHOULD MAKE YOU HAPPY!" to her father.