Characters
Now I did a job. I got nothing but trouble since I did it, not to mention more than a few unkind words as regard to my character, so let me make this abundantly clear. I do the job. And then I get paid.
— Mal

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker says the job brought only trouble and some insults about their character. So the terms are made plain and blunt: the work is performed, then payment follows. The tone is firm and aggrieved, insisting on the arrangement despite the fallout.
Context reviewed