When Snow returned home with her Mistress, the little royal was looking forward to meeting her 'dwarves' and 'princess charming'. Her role for the Master was as Cyralon's spy, thief and infiltrator, able to break into any place he needed her to and take what he needed. As a 'princess' among the Master's staff, she would be the leader of the Poppy Pack, the one they all would report to after Poppy and her sister Vixy. Of course, she kind of came up with her own little nicknames for the Pack, being very enraptured with her name and fable.
Why was Cherie her 'Charming'? Simply put, she rather liked Cherie when she was assertive or forceful. And the things she could do with handcuffs to the Princess...