In the last chapter of the Dragon Ball Super manga,
Beerus says that for using hakai he has to think only in destruction
Goku apparently tried to use hakai in the past, but it seems that he didnt master it since he says he failed using it.
Also, according to Dragon Ball, Goku can use the flying nimbus because he has a pure heart. Can a person like Goku with a pure heart do what Beerus says he has to do to use hakai?
Is Hakai a technique impossible for Goku to master?