Longman Dictionary of Contemporary English
personal assistant
noun
EXAMPLES FROM CORPUS
▪ I had been working for the Countess as a personal assistant since she married the Earl in 1976.
▪ It was this, Blanche said, that had pushed her towards phoning his personal assistant and arranging the interview that night.
▪ On July 23 Buthelezi's personal assistant, Zakhele Khumalo, resigned.
▪ The Secretary had in fact become a public officer, no longer merely the personal assistant of the monarch.
Wiktionary
personal assistant
n. Someone whose job is to assist and organize someone else's day-to-day business or personal tasks.
Wikipedia
Personal assistant
A personal assistant, also referred to as personal aide (PA) or personal secretary (PS), is a job title describing a person who assists a specific person with their daily business or personal tasks.
Usage examples of "personal assistant".
Why would you be his personal assistant, especially after Sterol used you against him?
Vanden Willard becomes personal assistant to the Organa royal family of Alderaan.
According to Paul, the politician didn't even know that his own personal assistant was a neo-Nazi.