It's likely a variant of
Justine. In French at least it sounds like "zhyus-TEEN" (long u, as in "few").
Googling the
German and Hungarian wikis I found no mentions of anyone named simply "Justie" - in those languages the name is translated as
Justina and Jusztina.
♥
Florentina Matilde '
Flynn' ||
Maximiliano Tomás '
Max' ♥