In terms of personality, Hildegard is very much like her friend, Amber. Snobbish, self-centered, and has a tendency to act aloof to those she finds beneath her. However later, in the episode "Baileywick's Day Off," Hildegard is seen showing a greater tolerance for Ruby and Jade, likely due to meeting them in earlier episodes.
Hildegard is also very proud and confident in herself. Her stoic persona are what separate her from the other princesses. Usually Hildegard will be seen wearing her haughty smile and carrying herself in manner that tells others she's "a cut above the rest." In fact, as Zandar finds out in trying to impress her, she is only truly pleased when in the spotlight.
In "The Princess Test," however, that image withers away. When Hildegard feels the pressure of an important test, she tries to hide herself away, not wanting her friends - especially Amber - to see her in doubt. However, Amber, donning the maternal role Sofia played to support her, offers some words of encouragement, and Hildegard regains her confidence, thus passing the test.
Hildegard, though mostly like Amber, does have some contrasts. Unlike the flamboyant Amber, Hildegard has a taste for the simpler styles. She liked Sofia's small garden tea party, saying it reminded her of countryside picnics. She is also willing to try new things if only to find something to impress her.
On Sora's TeamEdit
Hildegard, Clio and the other students at royal prep remain in Enchancia but usually visit the Team using their gems to visit their ship. Sometime some of the student, even Clio volunteer on missions, but sometimes claims Hildegard to go along too.