The best advice you have received so far is "Go to the store (the both of you) and hold them in your hand." I have a 12" Shun Chef's knive. Way to big for me so I gave it to my son. He has no problem holding it. What knife feels comfortable for a woman may have a handle that is to short and thin for a man's hand. Don't be afraid to buy two of the same knife, one for her, and one for you. If she can't comfortably control the knife, she will not be willing to use it.