I like it better than
Hilda, for sure! Wouldn't use it myself, because in English I think it has a very strong religious vibe:
Mary Hildegard especially suggests a nun. Which might well be what you want; if not, then I think a less common name would work better.
Frances Hildegard, or
Hildegard FrancesElinor Hildegard, or
Hildegard ElinorSuzanneAntoniaRuthGillianAnnabelAmyDeborah, for a vintage vibe (fn only;
Hildegard Deborah is uncomfortable)
Olivia, to bring it right up to date