Standard transliteration of 'Della' / 'Darla'.
黛 (dài, 'dark eye-paint' — favored in female names for elegance) supplies the 'de' sound;
拉 (lā) supplies '-la'. The most famous Della in Chinese subtitle culture is Della Young from O. Henry's 《
麦琪的礼物》 (The Gift of the Magi).