Has he started a bubble nest yet? He may be flirting with her, or trying to kill her, it is kind of hard to tell in most cases. I feel like their vision probably isn't the best, so he may not even be able to tell that she is a female.
After he constructs a bubble nest (if he does) I would say introduce them and watch them very carefully. I know Betta can be very violent breeders so it may seem scary. How big is the spawning tank? Just incase it does turn out bad, make sure she has a place to hide (or make sure HE has a place to hide, I have had an aggressive female kill a male).
Betta can be very tricky to breed, good luck!
After he constructs a bubble nest (if he does) I would say introduce them and watch them very carefully. I know Betta can be very violent breeders so it may seem scary. How big is the spawning tank? Just incase it does turn out bad, make sure she has a place to hide (or make sure HE has a place to hide, I have had an aggressive female kill a male).
Betta can be very tricky to breed, good luck!