Or you could go really bold and let them out for her to see. She would ask about them.... then tell her. One thing I have learned, the longer you wait the more mad (for not telling her) she could be about it.
I told my last GF, now my wife, about my diapers not long after we first met. She was single, divorced two years before we met and I had been divorced and again for about 10 years. My first wife knew nothing about my diapers, and once we separated I decided I'd never marry again without her knowing all about my long and deeply embedded diaper love for wearing, wetting and getting off in diapers. It first started when I was in my teens and I was in my early 60's when we first met. She was 34 with a young daughter. We first met at a popular local bar and grill, a well-known place for singles looking to hook up. The first night we met, I had my cloth diapers and rubber pants on under my trousers and was already a little wet. She was the one to first start talking with me and we ended up spending the rest of the evening in conversation, really enjoying ourselves and learning we had much in common. No word was mentioned about diapers or anything sexual and I told her how much I enjoyed the night and wanted to see her again. She felt the same so we made a date for dinner the coming weekend. I was fairly soaked when we parted that night, not to mention more than a little aroused. That weekend we had a wonderful dinner together, again endless conversation and we knew we'd get together again soon. Still said nothing about diapers, but we did talk more openly about our marriages including some sexual stuff. Again I was diapered but said nothing about it, even though I had wet several times with her and very aroused. I loved looking at her, very attractive, nice figure. It was the summer, she didn't wear a bra and I could see the outline of her breasts and areolas, with her nipples sticking out from her blouse and I was so turned on. I knew I was falling for her, but was not yet ready to break the news. The following few days were a nightmare, knowing I had to tell her, but so afraid she'd reject me when I told her my secret. The next date we again went out to dinner, but also made plans for her come over to my place for after dinner drinks.
I once again dressed to the max, diapered up, and picked her up from her place. We had another wonderful evening and near the end I very solemnly and quietly told her how much I loved being with her, and wanted to have a relationship with her, but she needed to know something about me that was very important. I could see in her face how worried she became, even scarred, as she said to go ahead, she wanted to know. So I did, I told her that I was wearing diaper and rubber pants right now, that I had wet myself a few times during dinner and that I wanted to continue to see her but I couldn't give up diapers. By then she was rigid, seemed very uncertain, but didn't get up to leave or yell at me or throw anything at me so I went on to tell her how long this had gone on, how it started, just everything I had been through to try to give up, hide, conceal my diapers from everyone and how unhappy it had I had been keeping all this to myself. She asked if I had some medical problem that required diapers and I told her no, it was more of a sexual fetish that attracted me. She kept asking questions, listening to me, but while a little distant, still friendly at the same time. By now the restaurant was closing, so I asked her if she wanted me to take her home, or do what we planned, to go to my home for drinks. She said, “No I would like for us to stay together for awhile and when we get to your car, I want you to show me what's underneath those lovely trousers you have on. Well, I helped her into the passenger seat, sat behind the wheel and asked ”now", she smiled yes, and I undid my trousers, lifted my butt and pulled my pants down so she could see me in all my glory-soaking wet diapers and rubber pants. She placed her hand on my crotch, rubbed my rubber pants and said “I've been wanting to do this since we first met.”