Hello!
betta breeding is not as easy as just putting a female in a tank... it takes way more than that.
http://www.bettacentral.com/breeding.htm
it is a lot of money and research, I would suggest you remove the female before one of the two gets hurt, and please read the article.
you need a special setup and and a lot of practice and patience, special conditioning for the pair, special spawning techniques, live food for the fry and A LOT OF TIME and MONEY to take care of the many babies.
good luck on the breeding. I would recommend that you research first before trying anything. Otherwise you might end up heartbroken and frustrated. Other than that, with the enough research, money time and set-up it should be an enjoyable experience.
good luck!