Trust Christ’s love and redemption.
"Come on! ye prosecutors! ye false swearers! All hell, boil over! Ye burning mountains, roll down your lava! for I will come out on top at last. I have more to boast of than ever any man had. I am the only man that has ever been able to keep a whole church together since the days of Adam. A large majority of the whole have stood by me. Neither Paul, John, Peter, nor Jesus ever did it. I boast that no man ever did such a work as I. The followers of Jesus ran away from Him; but the Latter-day Saints never ran away from me yet...When they can get rid of me, the devil will also go." (FLDS/LDS "Prophet" Joseph Smith, History of the Church, Vol. 6, p. 408, 409)
Witnessing to others isn’t not trusting Christ. Christ can and does work through others and witnessing is part of following Christ.
Those of us who have been there (ex-Mormons now Christians) like SZ and myself would probably not have seen the light if others were not led by their love of Christ to tell us we were following a false Christ and headed for a very real Hell (which the LDS do not believe in).