Rent Undercover Angel (1999)

Harrison Tyler is a struggling pulp fiction writer who just can't find love. When an ex-girlfriend shows up at his door asking him to take care of her six-year-old daughter for a month, Harrison ends up with more than he bargained for: a little girl determined to play matchmaker for him. The youngster manages to find Harrison a girlfriend, but when her mother shows up to claim her, Harrison finds that his life isn't the same without the six-year-old and he must fight for the little girl that has changed his life.