Ending Idea

different guy... wrong mark. Don't actually see who he is early on. Description of a person called 'Sam' or someone else which works with both sexes (eg alex, jo,George, Robin...etc). Description given along with this name is brown hair, 5,4 slightly overweight with big chest and is checked in the Motel opposite room 'blah'.
Our hitman trying to take out mark throughout film. Messes up a number of times. Final scene. he walks over there kicks ass and a quick show down at the end as OUR assassin takes out this fat guy but he puts up quite a fight with a gun as well... then end of the film... sexy lady walks in ...and stands in the doorway... you see somekind of mark or tattoo on him or his gun to see he's hired as well and they both lie their in agonising PAIN.... ok so I need help with the finale still...but thats the twist.

Other ideas - guy has a twin?
Guys a cop.
Guy is waiting for the assassin and planning to take him out.