In one of the greatest movies of all-time, Kyle Reese tries to explain to Sarah Connor how dangerous this thing called "the Terminator" is:

Kyle Reese: Listen, and understand! That Terminator is out there! It can't be bargained with. It can't be reasoned with. It doesn't feel pity, or remorse, or fear. And it absolutely will not stop... ever, until you are dead!

Sarah Connor: Can you stop it?

Kyle Reese: I don't know. With these weapons? I don't know