Susan Hayward is wrong for this role
Don't get me wrong, I love Hayward - "I'll Cry Tomorrow" and "I want to live" are two of my favorites. But she was a terrible fit for this role. She's not believable as a struggling young artist trying to get her big break. She exudes the confidence of a powerful woman, not some young thing who doesn't know how to handle a lecherous old sot in his hotel room.
And unfortunately she looks old enough to be John Gavin's mother. Even though she's still very attractive, she's 44 and he's 30 and looks younger. If they are going to put her in the role, they should have at least given her a leading man who was in his 40s as well.