I precept frequently (by choice) and I don't agree with that statement. A great beginning with a joke and a smile at 0700 does not guarantee success. Motivated, capable individuals may start at the very (sometimes painful) beginning of the learning curve ... but they learn and adapt.
I also would never say that to an orientee, as if I were the Great and Powerful Oz. I'm not. In addition, it's my job to make it work
... to produce a reasonably well-adjusted, functional nurse at the end of the orientation period, with performance in line with their level of experience. Unless the hire/interview process has been completely dysfunctional, or the orientee decides it's not for them ... my job as preceptor/coach/cheerleader/taskmaster/etc. is to make sure the orientee knows his/her strengths and also is actively working to grow and to correct deficiencies. With rare exceptions ... I have been successful.
Good luck to you, OP. Welcome to the ED.