As mentioned, it would probably depend on the temperment of the fish. One of my largest Kissing Gouramis (8") is as friendly as can be, and has never had any issues with tankmates. One of my little ones (2") is aggressive as anything, and a Betta probably wouldn't last too long with that one. Another issue would be the size factor...Kissing Gouramis need a large tank, because they grow big, and I doubt Bettas would be happy in that size of a tank. And swimming with an 8-10" fish everyday (Or hiding from it) would probably be stressful for the Betta.
I, personally, would not risk it.