I agree 100% with Derrel on the “real” thing… that is essentially what I was going to say, so no point in repeating it.
I really like the lighting in this photo—not only the nice shadows and the resulting colors, but the balance with the background. I know it’s a matter of taste, but the latter is something that often kills shots like this for me; the photographer goes to great lengths to ensure that the subject is vibrantly exposed with nary a mole or shirt wrinkle obscured in shadow, but the subject looks like he/she is part of a green-screen experiment gone awry.
I mean, most of us here can identify a flash-exposed subject when we see one, but when you glance at a photo and the first thing that registers is !!!!!!!! FLASH WAS USED HERE !!!!!!!! then it’s kind of a drag, IMO.
Oh, and one more thing—by no means do I want to discourage you from picking up another strobe, but don’t discount the use of a reflector on a shot like this as a lower-cost way of getting some fill.