You never want someone to reject truth. But if you're going to teach something that hasn't been understood before, you have an obligation to make the matter clear. You should prepare the the audience by laying a foundation using existing scripture, teachings and knowledge to show how the new concept fits into the existing framework. Just declaring something without a foundation to support it often offends instead of enlightens. It alienates rather than invites.
I'm somewhat concerned about those who try to get an understanding of what I've taught, but who haven't read what I've written. In the material, I walk through existing concepts, accepted doctrines, recognized scripture, and language of Joseph Smith to first lay the foundation. Much of that may be familiar; some of it may be surprising, but I take the time to lay it out. Then, after clearing the path to the next ideas, using the existing body of recognized material, I go forward with something that may be new, or difficult, or challenging.
The book I am working on right now will introduce some important information that most people are unfamiliar with. But it will walk through, in the same patient way, building the foundation from which the conclusions are inevitable, and fit it into the framework of all that is known already. I know there are those who are unkind, impatient, or who don't care about the audience. They will want to blurt out the conclusions, and only move quickly to the startling points. That is inevitable, I suppose. But anyone who does that is neither a good teacher, nor are they kind to their audience. They don't care if someone rejects truth. They just want to be involved in the sensational, the surprising and the titillating.
Anyone who is going to teach has an obligation to bring along, in a kindly way, those they seek to reclaim from error. That's how Joseph put it. If you think you have some truth and want to remove an error, you have an obligation to proceed in a proper and affectionate manner to reclaim them. (JS-H 1: 28.) When a new truth is introduced in a harsh, challenging, unkind way it will be disturbing, upsetting and alienating. Such a person is not a teacher, but instead an enemy to the truth. They make it hard for people to find their way back to God. It is wrong.
True teachers will always adapt to their audience and show kindness and patience to those they teach. When they are called upon by the spirit to rebuke with sharpness, they will afterwards show an increase of love, to make it possible to accept the inspired rebuke. (D&C 121: 43-44.) They want to bring people to a position where truth spreads, is accepted, and all can rejoice in the new light and knowledge shared between them.
This is not to say that all truth a person has should be always be shared. Unless the right circumstances arise, with a properly prepared student to instruct, some kinds of knowledge cannot be shared. But to the extent something is appropriate for instruction, the lesson should be adapted to the capacity and preparation of the audience. Some material may be appropriate with one person that would be inappropriate for another. Until an audience has first been taught basic information, they are unprepared to hear something further. We don't discuss some things with investigators, but leave it until later for them to be taught. It takes about four years for a convert to receive the basics of the church. It takes years before some information can be put into context. Rushing to expose people to information is not only hasty, but oftentimes destructive. If you intend to be a teacher, and not an enemy to someone's salvation, you should only proceed in the appropriate way, using kindness, meekness, gentleness, pure knowledge and love unfeigned. (D&C 121: 41-42.) Not haste, shock, surprise and ambush.