Better personality tests include measures of faking that can help detect job applicants who are less than truthful. Most personality tests do not appear to have discriminatory effects, but you should be sure the test publisher can provide documentation of this prior to using a particular test. Similarly, the test publisher should be able to provide documentation of the test's validity. If you can't get this information, don't buy. Studies show that many job applicants dislike personality testing.
Many people feel that their inner feelings are none of an employer's business.
Chosen carefully to measure critical employee attributes, personality tests can be one additional tool in the search for the optimal job candidate. But they are not an easy solution to all your hiring problems. Remember, no test of any kind absolutely CAN predict future performance. Or even come close. Any attempt to sell you a test on the basis that it will take care of all your hiring problems is a scam.