I have a 1 male and 1 female together in my 140g tank. I have also been successful with keeping male and female betta together in a 30g tank. The reason you are finding conflicting info is because a lot of the time it depends on the personality of each individual fish. Plus tank size is a major factor. The bigger the tank, the more places for the female to chill out when she's sick of the male chasing her. I don't know if this info is true, but I read that male betta that have dark maroon faces tend to be more aggressive and also that wild caught betta are more aggressive too. Could just be a rumour though. It's just a risk that you'll have to take if you want to keep them together. I personally would advise against keeping them together in a small tank, but that's just my opinion. I would also have a back up plan on what to do with the fish if it doesn't work out. Most fish stores in my area will take them back but you should check with your local shop to make sure. Hope it works our for you!!
Good luck!