Adding "breath" to a voice-over

Any suggestions on how to add "breath" to a spoken female part?
I want to add "s3x" to a woman's voice-over.

Quite an interesting question!
First things to try that pop in my mind (used very subtly) are chorus, harmonizer and distortion. That's to create a more misty, deeper "bedroom tone" :o). Maybe some EQ is needed as well, and advanced pitch-shifting, as Danny suggests, depending on the type of the voice.

Say, doubled track, the other one quite low volume, panned 20-30% off from the main voice, with distortion or something.
This all is just imagination, I've never tried anything like that for spoken voice, and it may be these simply don't work at all.
 
Compression, maybe parallel, should be tried, too.

I'm guessing there's no way to re-record the spoken word part?

If a "do-over" is out, perhaps you could have a different woman read the part, with the breathiness included, and combine the two.  You could also try having that different woman attempt only the breathiness, and then incorporate that into the spoken word.

I'm not familiar enough with any post-production techniques to achieve what you want.  I worked in commercial radio 20 years ago, and women either had or did not have that bedroom voice.  Yes, smoking two packs a day can help, but that's only going to deepen an already attrractive speaking voice.

In the past I have recorded myself doing just the very starts of letters like F, C, J, Q, V, H, T and S sounds etc. You can do them quite softly. And cutting and placing them on a second track right under the starts of words that need them and the correct ones. They come in handy for other things too. Like giving song vocals more diction.

Filter out the low end when adding these things to females. And the second track is very soft of course only barely noticeable. It works pretty well. 

I wonder why it is so breathless. I like to record voice overs up pretty close to the mic. The pop filter will take out the plosives and you get all that lovely up close and breathy stuff naturally with added detail. Much better signal to noise ratio too. It is good to add a little low end to any voice over. The proximity bass boost adds the low end rather naturally and is easily controlled.

Cool.