A confidence man is essentially a "sure-thing" gambler.

It had been Larry's practice, before the law had tripped him up, to study every detail of an enterprise he was planning to undertake, to know the psychology of the individuals with whom he was dealing, to eliminate every perceivable uncertainty: that was what had made almost all of his deals "sure things." Strip a clever knave of all intent or inclination for knavery, and leave all his other qualities and practices intact and eager, and you have the makings of a "sure-thing" business man:--a man who does not cheat others, and who takes precious care that his every move is sound and forward-looking.

Aside from the moral element involved, the difference between the two is largely a difference in percentage: say the difference between a thousand per cent profit and six per cent profit.
The element of trying to play a "safe thing" still remains.
This transformation of character, under the stimulus of hard, steady work upon a tangled thing which contained the germ of great constructive possibilities for some one, was what was happening unconsciously to Larry..