I don't think she is nearly that clear in her own mind about what she is doing.
I'd agree with not being clear up until the sunshine scene, she says it herself on day 10 at the bar
Vicvian "I created a contrived situation so that I could, more or less, assault on him"
She pretty clear and knows what she is doing... the why, on the other hand...
Sunshine "Well, this man obviously awoke some hidden desires you thought weren't there."
Vivian "But I hate him! So why do I want him?"
Sunshine "You know, some of the best sex I've ever had is with guys I hated"
A four-line conversation, and it gives us the why. Simply put it's the sex and again on day 10 with sunshine, we get the following conversation
Vivian " I thought back to something my mother told me long ago..... She told me to have fun while I was single, but said men wouldn't marry wild women.... At that point I was starting grad school and already working as a student educator. I was ready to move on from my youth and was thinking about my career and starting a family.... So, I closed that chapter of my life and started a new one.... I wanted him to respect me, to believe I was a chaste woman, so I made him wait... a really long time. And I never did certain things so he would think I was a lady. "
One statement from her mother made her change her whole demeanour and personality, all because she's trying to be the woman she thinks Hutch wants - not the actual woman she is - Now, what her past is doesn't matter, but Christian awoke something in her, Sunshine helps her realise what that something is - shes giving in to her desires and she knows it and rather than being someone else and the woman she thinks Hutch wants, she being herself and the woman Christian wants.