A person’s different conclusion may reflect a different cost, not a failure to understand you.

Disagreement is usually diagnosed as misunderstanding, because it is more comfortable to think somebody did not follow you than to think they followed and chose otherwise. Often they weighed the same facts against a different set of consequences: their savings, their health, their family, the thing they cannot afford to lose. Explaining more slowly does not touch any of that.

When a person lands somewhere you would not, ask what it would cost them to do it your way. The answer tends to explain the whole disagreement in one sentence and saves you from repeating yourself.