I agree strongly with Nishnabotna about being "professional" and doing the training the best that you can which produces the "best product" of that training. Your behavior and attitude will be observed and noted by those that matter. If the "thorn in your side" refuses to be trained or proves incapable of the proper utilization of the training that you've provided, then that will also be noted by those that matter.

As suggested by MoBob; After the training has been completed, stay out of the "thorn's" eyesight OR thus be placed in a position where YOU have to bail him/her out. After the training has been completed, "It's sink or swim time" without your involvement.

Just my thoughts.