Do you know how old they are? You should expose them to each other for a few minutes a day so they recognize each other. They both need to be in excellent health. The male needs to be capable of making a bubble nest; they should be blowing bubbles on their own anyway, as this is an indicator for a happy and healthy fish. The female will start getting egg-fat and have vertical stripes if she's ready to be bred.
There are a few very informative posts about how to breed your bettas in this forum; please read them thoroughly and ask any questions you have before you start! We want you to be ready for anything that could happen
