There’s no way that you can say anything without risking her feeling insulted or hurt, simply because you can’t control how she’s going to react. But it’s worth the risk to try to fix a situation that clearly is not working for you, because clearly this has become an untenable situation. Use “I” statements to make it less about her and more about you, and also suggest some changes that you can make. Something along the lines of, “I’ve noticed that due to the way that the office is set up, you can’t help but overhear my conversations. It’s really difficult for me to stay focused on phone calls when I know that someone else is listening to them because I get distracting thinking about how it sounds from the outside. I can shut the door for private calls, but can we please agree not to dissect my work-related phone calls together?”