Final answer:
The most likely diagnosis for this patient is antisocial personality disorder, characterized by a lack of concern for hurting or using others and a lack of remorse for their actions.
Step-by-step explanation:
The most likely diagnosis for a patient who is charming but shows no concern for hurting or using other people and shows no remorse for their actions is antisocial personality disorder. Antisocial personality disorder is a mental disorder characterized by a persistent pattern of disregard for and violation of the rights of others. Individuals with this disorder often manipulate others for their own gain and have a lack of empathy. They may engage in destructive behaviors without guilt or remorse.