Variant of Layla, and the usual Persian transcription.This spelling was used by Lord Byron for characters in The Giaour (1813) and Don Juan (1819), and it is through him that the name was introduced to the English-speaking world.
From Latin dulcis “sweet” and bella “beautiful”. The usual medieval spelling of this name was Dowsabel, and the Latinized form Dulcibella was revived in the 18th century.