Until Sombra was defeated, Hearts Desire was kept away from her father after she had shed her crystal cocoon to appear as a young filly. Denali Snowfall (her father and the Crystal Heart) had been confined to a weakened cocoon and hide away inside his Crystal Heart form to conserve energy and stay alive.
 
He was vaugley aware of the forming of his daughter but did not have the strength to protect her. Because of this, Sombra stole her away and locked Denali away until Twilight her friends were able to rescue him. Originally, she was born out of a surge of desire from the Crystal Ponies for Sombra to be defeated.
 
While Denali was locked away, Sombra kept an eye on Hearts Desire. She was resentful to him and often fought against his demands. Seeing how she was not truely the Crystal Heart but a mere fragment, he saw no reason to take her magic and instead used her as a bargaining chip to keep the Crystal Ponies under his rule.
 

 
 
Character(s), Art: EyesoreForTheBlind
 
Base Used: https://www.deviantart.com/crystalponybases/art/Cuddle-Hug-757768488
 
Background Used: https://www.deviantart.com/vector-brony/art/Crystal-Throne-396020979