Why does Ruth quit her job at leather factory?

Ruth works at her Aunt Mary's leather factory, where she met James's father, Dennis. Eventually Ruth could no longer tolerate her aunt's bad treatment of her, and quit her job at the factory.

She quits her job at the leather factory because she has met Andrew McBribe, an African American and her eventual husband. Her family disapproves vehemently to her choice, and as her aunt owns the factory she makes her decision accordingly.

Thank you! Aslan and jill

Also, I may have confused you over the metting of her future husband. The two don't immemdiately fall in love and cause Ruth to leave her job. Another reason she left was to get a job doing something a little more fun............. like find employment near or in Harlem.