Evaluating Grover's algorithm on 3-SAT
"Measuring", in quantum computation, is the act reading the quantum state along some basis. This will cause the the quantum state to collapse. The quantum state after grovers algorithm is such that it collapses with very high probability to the desired result (in this case an assignment). Perhaps you should check the result because it might just be a bad case, that is just unlikely, but you don't have to check the result to get the output of grovers algorithm. You just have to measure it. To determine with high probability weather or not the formula was SAT you should check the assignment that it gave out.