Yes, that Natalie Portman youTube video of her speaking flawless Hebrew is a good example of how she really is at her sexiest when she speaks Hebrew.
The Ten Commandments is my favorite movie of all time, but I am also well aware of its many flaws. The most glaring of these faults is probably just the one mentioned above, the love triangle between Moses, Nefretiri, and Pharoah. In my many decades of Torah study, not once did I ever come across such an absurd idea. It was a total Hollywood fabrication.
I suppose it is a trade-off. These days, when Hollywood makes historical movies, they try to depict things as accurately as possible. Unfortunately, their values are totally corrupt. Back in the day of the Ten Commandments movie, they were clearly not conscientious about depicting history as accurately as they can. On the other hand, Hollywood in those days did have their values intact, and in fact Cecile B DeMille himself lived as a devout Christian. I say lived, because the truth is, he was a Jew.