IDIOMS

square shooter

(idiomatic) A person who is fair, trustworthy, or forthright; a person who bargains or transacts business in a fair, honest manner.

Example: 1929 Jan. 7, Manning Vaughn, "Putting 'em on the pan," Milwuakee Journal, p. 5 (retrieved 3 Sep 2012):
  For years he was in a position where a bribe, the turn of a crooked deal, a "queer" fight decision might mean thousands to him. But he was ever the square shooter. The crooked finger of scandal was never pointed his way.
1992 July 6, Walter Shapiro, "Spelling Out The Job Specs," Time:
  "I suppose it's because I have credibility as someone with integrity and as a square shooter."
2000, Matt Braun, Kinch Riley (2007 Macmillan reprint edition), ISBN 9780312948535, p. 16 (Google preview):
  He'd always been aboveboard, a square shooter from start to finish.