Great question, Jeanne. I think a lot of people are unclear on this. It’s tricky.
The difference can be subtle, but it is question of emphasis. Women’s fiction is mainly a woman’s journey, which can certainly involve a romance, but the emphasis is on the woman’s development of her life. A romance is about the development of a relationship. The emphasis is on both characters interacting and growing together. They usually connect early in the book (sometimes even on the first page!) and the book concludes with their commitment to the relationship.
Hope this helps!