I wouldn't. Danios are sort of manic and while female bettas do have moments of speedy going, I don't really think they appreciate the zippyness of the danios.
Hello, I agree with Jaylin. Danios are very fast moving and Betta are very slow moving. Danios will get all the food and Bettas could suffer. Also Danios need a much larger space because of their speed and movement. On the other hand Betta need just a very little space.
Good luck in your choice.
Gianni
female bettas, are anything but slow.. i've had 3 in a 90 community /neaons,glofish, and cherry barbs plus other fish and they never bothered the other fish except for their own kind..