Well from one of the Bustey Women Shooters(38D), I dont have a problem with the string hitting the breast once I found the proper draw length When shooting a non steep angle, the proper draw length acompained by the proper anchor point should keep the string in front of the breast. There are Chest Protectors on the market for use in archery.
Where the problem for me learning a shooting stance that allowed me to keep the string off the breast so the string would not contact my clothing and or breast and throw the shot off,You would be suprised by how much the string contacting my clothing and breast was throwing my shots off, once I found the right shooting stance , that also caused me to find the right grip, wrist position, bent elbow and shoulder position to open up my stance a little, I also found a slight twist in the waist towards the target would bring the string up off the breast a bit.
I also found that by raiseing the draw elbow at full draw causes the bow shoulder to drop some thus helping to drop the breast away slightly from the string. I did have to spend some time learning to ajust my shooting form at a step angle from a tree stand, the stepper the angle the more the string would contact my chest, its just one of those shooting positions that I had to work thru and dont think I could even begin to explain how I solved it, SORRY.
I can tell you that a sight level did wonders in helping me , a off plum bubble started to tip me off to the string contact situation when I knew it wasnt bow torque.
I hope your wife has a great time shooting with you, and enjoy your time together shooting, best of luck .
Deborah Knoff