Worthy character is best forged from a life of consistent, correct choices centered in the teachings of the Master.
There are powerful emotions that bring two people together in wonderful harmony in a marriage. Satan knows this, and would tempt you to try these emotions outside of marriage. Do not stir emotions meant to be used only in marriage.
The Book of Mormon is concrete and solid, they can hold it, and they can visualize that they have to pray to decide if this physical thing is true. There is no room for interpretation.
No one had to worry about Peter after his conversion. Your investigators can be that converted.
If we are not careful, we will convey the message that investigators have to be perfect. Not true!
Can you hang in there with your investigators when things get going tough? Don't give up on investigators because they have a little weakness. Work with them until the Holy Ghost tells you not to.