Female Assistant tracks Billionaires daughter to Texas

I'm trying to find the title of a book about assistant to a Billionaire who is in charge of his daughter, who decides to run off to Texas to find herself a cowboy. The heroine of the story (the assistant) is trying to track down the daughter with the help of the new security guard (who is her love interest) I also remember that the heroine has arguments with her dead mother inside her head. Any help on finding the title or author of the book would be appreciated. Thanks!

Bump.

Doesn't ring a bell with me, I'm afraid. This was a romance? Any idea when you might have read it?

It was a romance. I read it about 3-4 years ago, it's a fairly modern book. I'm pretty sure the dead mother's name is Sunny and the assistant also ended up reuniting with her long-lost sisters at the end.

Bump.

Bump.

I think I found it: Some Girls Do (Warner Forever) by Leanne Banks. From http://www.leannebanks.com/some_girls_do.html
As personal assistant to the rich and eccentric, Katie Collins thought she'd heard it all. Now to keep her job she has to play matchmaker for her boss's only child. With her shapeless clothes and prim appearance, Katie has not had much experience with the opposite sex. That doesn't stop her from trying to turn shy Wilhemina into a swan. Or from dragging reluctant bodyguard Michael Wingate to Texas, where their lovelorn heiress has run off to lasso herself a cowboy.

THANK YOU SO MUCH!
I've been looking for this book for ages, I never thought I'd find it again. :D

You're welcome!