Am 30(m) dating a girl, whos mouth stinks. Girls, is there a polite way to tell her? How do I not offend her?

I started dating a girl recently. She is all cute and pretty. Nice person. We really like each other a lot. After going on couple of dates, we wanted to kiss. Her mouth stinked so bad. It was around 11 in the night something. Since it was after a full day work, I assumed it was bcz of her tiredness. The next time, we met in the morning and went I kissed, it was horrible. I cudnt kiss at all. I struggled to stop kissing her but she kept trying to kiss me. Then the third time, I was literally scared to kiss. So i met her in public, while departing she wanted to kiss me so bad and literally gave me a one second kiss. It was outright bad again. How do I tell her politely? How do I find a solution for this scenario? I really like her but this thing is just disgusting. Once in a while my dog licks my face in excitement and it smells better than this girl.