The 19-year-old girl, who was a third-year student in an arts college at Tiruchengode, had come home on leave on January 26 to Krishnagiri when her mother forced her to get engaged despite her protests, police said.
The deceased wanted to complete her education in order to get an officer's post in her late father's regiment, they said.
The girl returned to the hostel room yesterday and consumed poison, police said, adding, she was rushed to a hospital but died en route.