What prompted her to marry curley?

She didn't get into pictures, and she wanted to get away from her mother.

"I tell you I ain't used to livin' like this. I coulda made somethin' of myself." She said darkly, "Maybe I will yet." And then her words tumbled out in a passion of communication, as though she hurried before her listener could be taken away. "I lived right in Salinas," she said. "Come there when I was a kid. Well, a show come through, an' I met one of the actors. He says I could go with that show. But my ol' lady wouldn' let me. She says because I was on'y fifteen. But the guy says I coulda. If I'd went, I wouldn't be livin' like this, you bet."