Van Heflin, according himself, was told that he would never get the girl at the end of the film. This can certainly be seen in probably his two made famous films, at least in modern times, of Shane and 3:10 to Yuma. Funny enough he actually gets the "girl" in both of those films so to speak, but in both of those films he plays the more bland average man character, as written, compared to the more flamboyant individuals of Shane and Ben Wade played by Alan Ladd and Glenn Ford respectively. The reason I mention this is in this film because both of the two main women of the film are both rather blunt in displaying their affections toward Heflin's character. One being his old childhood friend the titular Martha Ivers (Barbara Stanwyck) who is married to a man named Walter (An against type Kirk Douglas since it was his first film before he even had a type), and another being a troubled woman Toni (Lizabeth Scott).
Van Heflin is actually kinda against type himself by playing the technically romantic lead which is interesting since his character starts out as the more troubled child. Even though he is drifter who does some gambling Sam is in no way a malicious character. It is interesting to see Heflin, who was obviously being very generous to his co-stars in those later westerns he made, since he proves himself to have quite the charm when he calls upon. Heflin carries himself well with a certain slick devil may care manner as Sam first arrives into town and he just seems to be enjoying his time of soaking in the nostalgia of being in his old hometown. His instant befriending of Toni is made wholly believable by Heflin's performance. He has a great easy going charisma here and he does a great job of establishing Sam as a likable guy, and his work here makes it a bit surprising the way he was often given the role as the other guy.
Heflin does well to kinda establish Sam outside of the melodrama a bit as his performance always feel very reserved well the emotions start flying quite freely with the other characters. Heflin's take with the character really works because he frankly presents Sam as basically a reluctant participant in the almost absurd level of drama that takes place involving Douglas's and Stanwyck's characters. This makes the most sense because Sam is not only tricked into staying more than once by Martha, but this also leads to him being constantly harassed by goons hired by Walter who happens to be a politician with some local sway. This leaves Sam as basically a man who just wants to leave possibly with the young woman he happened across. Unfortunately for Sam Martha keeps making her advances which leaves Walter to also become increasingly desperate as well. Heflin is great by portraying just the very down to earth exasperation of dealing with the insanity he'd rather not be a part of.
Van Heflin does some fine work here by resisting the urge ever to become part of the melodrama and it is perfect for the character of Sam who is really pulled along to the plot. Heflin is able to somewhat alleviate the intensity of the melodrama by playing Sam in just a rather charming and honest fashion. This does limit his character arc somewhat in that he mainly becomes disillusioned with his old friends, but Heflin handles this well by just being so genuine in his depiction of Sam's reactions throughout. The film isn't a great success but Heflin is essential to keeping it on a rail as he brings some power to the situation by portraying how a sane man would respond to such insanity. He kinda stabilizes the melodrama in a way but as well offers enough relief through the surprisingly amount of charm that he does bring into the role. It's very solid work from probably one of the most underrated actors from the period.