If you're talking about people who tell the truth most of the time tend to get the truth told to them, while people who don't tend to get lied to a lot more - I'll kind of buy that. That's the old sugar for sugar, salt for salt thing. I know that being truthful with people has led them to be truthful with me, telling me things that they would never share with anyone else. I also know that people who lie a lot are pretty easy to lie to, and people who tend to truth are harder to lie to.
But, if your talking some sort of karma deal, then I'm not so sold. I've seen far too many examples of human scum bags having awesome lives, and of good, decent people getting nothing but suffering and abuse piled on them. I'm convinced that that's why the 'karma' faith systems had to invent reincarnation to get around the fact that pretty much everywhere, and throughout history, karma seldom works out in in real people's real lives in that nice, neat morality play.
And I should add that I tend to truthfulness not out of some superior morality, or because I have some sort of core value like the 'radical honesty' people do. I tend to truth because: a) I'm not creative enough, and quick enough to do those kind of mental gymnastics all the time and what little creativity I have I choose to use on other things, and, b) I'm really, really lazy. Really. And I don't want to have to constantly expend the energy to keep all those stories straight, and to always have to be thinking 'what did I tell this person?'. If you tell the truth you never have to do that.
The fact that - a lot like choosing to be happy and live in joy - it just pisses so many people off is just a bonus.