Laura's Take:
Could Latimer truly read Alfred's mind and yet proclaim that Alfred has no doubts whatsoever. Surely all men have doubts, even small ones, but no mind could be completely complacent.

The Class: Its true that Latimer is angry at Alfred but it seems he doesn't really know him at all. Alfred has always been the father's favorite son, evoking a feeling of resentment within Latimer from an early age. Latimer becomes a discredited source when he proclaims Alfred would find no evil by not marrying Bertha - for we know that one day Alfred does find evil, in death.
"The fear of poison is feeble against the sense of thirst"
For Latimer to acknowledge Bertha's true nature he would have to accept that his visions are not accurate That he is in fact imagining all that he sees and that his foreknowledge is not factual.  In other words he does not have the powers he thinks he does. But by admitting this he would be discrediting himself. Perhaps also we could think as to whether it may be impossible to project onto someone you truly love. Or does Latimer not truly love Bertha at all; does he only love what he envisions Bertha to be..? Perhaps Latimer's projection reaches out in two extremes; on one side he idealizes her- on the other size he demonizes her. Could his ideals of Bertha have spawned from his mother's angelic upbringing towards him?

By assuming to know everyone and their shortcomings, you place yourself on a pedestal far above all, when, in reality, you have as many faults as everyone around you. Yet it is your refusal to acknowledge these faults that leads your to occupy your time  concerned with others.