That's like saying all of the trustworthiness of a used-car salesman.
To the OP: Learn Ruby. You'll get much better with it much more quickly, you'll be able to use it for far more than C or Java (particularly on the Mac), and most importantly, you'll actually enjoy using it way more than C or Java. And when you get the basics down in Ruby, you can go off and learn other languages. And as you learn the "features" of other languages, your reaction will likely be something along the lines of, "Oh, I get it. That's just the hard way of doing something that's straightforward in Ruby!"
That said, there's a value to learning C, in that there's a value in knowing how to take apart an engine and put it back together. But you're best off learning how to drive before you tackle that task, and guess whatC makes you build the car before you can actually start driving. Java's a bit better, in that it's more like assembling a car from a kit, but the downside to that is that you're still just following directions because "that's the way it's done", but you won't have a clue why it's done that way for a very long time, if ever.
Ruby, on the other hand, puts you in the driver's seat from the get-go. And as you learn the language, you'll realize you have way more control over the car than you knew at first, and you've actually learned way more in the process than you would have with C or Java.