Is it "once" or "If"?

    Many Christians believe the Bible teaches assurance of salvation.  My pastor claims to be one of those.  He is always expounding that Christianity is a "know-so" religion and if you have doubts about your salvation you are lost.  But he also says that one must "get right in order to live right in order to die right',  a philosophy that seems to teach salvation by works rather than faith.  Our church has lost a few members because he confuses people about what he believes.  Do we or do we not have assurance of our salvation.
  The pastor says he does not believe in "Once saved always saved" but believes that "if saved always saved".  I think such statements only adds confusion and doubt.   I prefer the "once saved" version of that statement.  Christ only died once.  If one could lose their salvation Christ would have to be crucified as many times as a person lost their salvation.  Christ only died once because that is all that is necessary.   To use the phrase "If saved' begins a statement of assurance of salvation with a statement of doubt.  "if saved" sounds like anything but a sure thing.  It smacks of grace plus something else.  We are saved by grace, through faith, and that not of ourselves.  Grace is not conditional.  It is something given to another when it is totally undeserved.  All one has to do to receive it is to be willing to receive it. 
   I know why my pastor says if instead of once.  So many people claim to be saved that do not live for Christ that "being saved" has almost become synonymous with "I go to church or have been to church and I buy into the belief that Jesus Christ is a real person and did good things."   But saying "if"  instead of :"only" doesn't make one more saved  but it does add confusion.