How can you tell if your female betta is happy?

If you are feeding her the righ amount. If she has a big enough tank and she gets plenty of excersise. If her water temperature and PH is the right level. If you change her water at least every week. She should be happy. If you want to garuntee her happiness put her aquarium by another aquarium, because this will give her a chance to comunicate with other fish and will keep her from getting board, you can also get another female betta because female bettas get along. Don't get two or an even number because one will bully nthe other. If you get an even number you might as well get groups of two.