US Ambassador to Greece Kimberly Guilfoyle speaks during a dedication ceremony at the chancery of the US Embassy in Athens, on October 7. - Mark Schiefelbein/AFP/Pool/Getty Images

President Donald Trump is weighing whether to dismiss Kimberly Guilfoyle from her position as US ambassador to Greece after a string of reports about misconduct, a person familiar with the matter said Sunday.

Trump has been monitoring reports claiming Guilfoyle, who was engaged to Trump’s eldest son Donald Trump Jr. for four years, accepted lavish gifts as ambassador and sought money in exchange for providing access to administration fig...