If none of them is qualified as "best" , please make one according to the meanting they convey.

1)Decent man prefer the money from a decent resource.
2)Gentleman loves fortune and takes it in his Way.
3) The gentlemen make fortune in a decent way.
I definitely like (1) and (3) best, but they need a little repair work:

Either 'A decent man prefers money from a decent source' or 'Decent men prefer money from decent sources'.

Either 'A gentleman make his fortune in a decent way' or 'Gentlemen make their fortunes in a decent way'.

Or how about: 'A gentleman makes money like a gentleman'-- this one is subtle but effective (maybe).
A gentleman makes money like a gentleman!