Adding SSD to MBP (2012). TRIM?
There is no official way to enable TRIM on non-Apple drives. In all likelihood, idle time garbage collection on a Samsung 830 will be sufficient to maintain performance so you might want to ignore TRIM unless you see a problem.

I've been using that drive in a late-2007 MacBook for months even when the drive is full and have not seen any issues without TRIM. Not an exact comparison as the lower speed interface on mine might mask any problems but still a positive sign.