Indonesian to English Art/Literary Poetry & Literature early 20th Century Indonesian novel in Malay lingua franca

One of the characters in the book, a former maidservant, has become governess, more like a second mother, to the orphaned son of a Dutch sugar mill administrator. She takes on many of the duties of his late wife. People begin to call her 'Ndoro Mas Ajeng'. What is the significance/meaning of this title and how would it be expressed in English?