How to seduce my female partner for Anal Sex?

I enjoy sex very much with my partner, but she is extremely reluctant to have Anal Sex. I have tried many ways, such a lubricating her anus with lubricants, and sometimes even with medical creams for pain relief in anal region. I have also tried lubricants for anal sex, baby oil, lotion, cream, etc. I have tried to clean her bowel with anema before sex, so that she would feel clean. I have tried to lubricate her anus inside with my finger, including the ring of spinchter which is about 2 inches inside the outer opening of Anus. But She does not allow me to have anal sex with here. During last 10 years, I had been successful only 3 times, and that was also only insertion of the head of penis into her anus After that insertion, just 1 inche more insertion, she start screaming like hell and puts me away and that becomes the end of anal sex. ANY SUGGESTIONS / COMMENTS WOULD BE HIGHLY APPRECIATED. Thanks for you time. TC.