Abusive Relationship

I know this may be a rather hard topic to talk about but I’m lost and this is my last option. My question is do you believe an abusive man or woman can change their ways honestly ? Do you believe a person of this sort could actually move away from abuse & become a better person? Should you stay while they are “attempting to change” or is it better to separate and see if the change is really happening. This could be verbal, physical, or mental abuse ! Thanks in advance you guys.