With a charm person spell you can make one or more targets believe they are old friends of yours. They will treat you like a valued acquaintance and do small favours within their power. They will not risk personal harm to themselves or their other friends to help you.
Convince a person they are your friend. The target’s initial disposition will greatly affect the working of this spell. If a police officer catches you red handed stealing a fruit - the spell might make him go easy on you and let you go with a warning. But (unless very corrupt) he will not let you get away with murder.
The spell is useless against hostile targets or targets you or your allies attack or harm.
Charm spells are hard to detect, requiring a spellcraft roll vs. the casters Presence stat + his skill in this spell.