Frankly, I don't know what to tell you because there is no formula that if you do or say something, then someone who is anti-gun will turn. If that was the case, we wouldn't have to deal with the Bradys.
You may want to look up crime rates in your state and show your wife. Also try explaining to her how important it is you to be able to protect your investment and also your lives. I'm going to guess that getting here to the US and staring your own business wasn't easy, so you should be able to defend the new life you're starting. I just hope that it doesn't take looking down the barrel of a gun to make your wife realize that there are lots of not-so-nice people out there that will a) try to take what you have worked so hard for because they are too lazy to work themselves and b) may or may not have a problem killing you after they have taken what they want because they don't want to leave a witness.