There’s a difference between ability and capability.
Ability is assumption and predictibilty where as capability is definitive function and credibility.
Ability is trust whereas capability is faith.
Ability is shadow whereas capability is image.
Ability is belief whereas capability is believer.
Ability is suspicion where as capability is observation.
Ability is tendency whereas capability is potential.
Ability is Masking whereas capabilty is 

Ability is your succession where as capability is your exibition. (Dr Raza)