Here is my solution, you can create a text(add actor first), and say somthin like Hey Evil genius im gonna kick your but! then you add an object that you can hit with your main actor and then the text will appear, you would do main actor->any side of TextActor->Add Action, Create actor, then you would put the TextActor name in the box on top, then you hit immidiate action.
thats only if your character hits the actor text,or else there is no other way! Have him say "Nope, get your sorry butt over here."
and you can do that for your enemy to, like have him collide with an actor,displaying text, and do collision any side of da da da, create actor, text2. or somthing.
well thats my solution any way! Dont get mad if im wrong or somthin thats just somthing i threw together..