3mm gap, would bonding fix? (photo)

Yes, direct composite bonding is a great way of adding some width to your natural teeth.  Understand that each of your front two teeth would be 1.5mm wider, and then might look wider and slightly out of proportion in comparison to your other teeth. This can generally be accomplished in just one visit to a cosmetic dentist and oftentimes no local anesthesia (Novocain) is necessary.However, please realize that you would most likely get a much more attractive results by doing four porcelain veneers. 

You can achieve this look with bonding quite easily, and if you are ok with the proportions then go for it but it will make your two front teeth very large.