I believe the three greatest gifts a director can give their cast during the rehearsal process are time, repetition and the freedom to fail.
The human condition is funny. We are taught very early on that failure has a negative attachment to it, but when we take a closer look, the measure of our successes are really just making a marked improvement upon how well we did on the previous attempt. That's the benchmark.
Once you have mastered that concept, it gives you a tremendous amount of freedom to push yourself and try new things and still be okay if your attempts fall short.
The rehearsal space is a sacred and safe environment for the actors, and should always be treated as such.
Trust your process.