on change of belief by a former adversary

how do you make peace with the fact that the one person you've despised for their thoughts and ideas, whose thoughts and ideas were not only wrong but a moral evil, has convinced you.

they were right, nothing you fundamentally believe has changed but the specifics have changed, the good and the bad have now been jumbled up, and how one must react regarding the bad is bordering uncomfortable yet familiar.

neutrality cannot convince me, this is the only path forward, how do i grow accustomed?