Their sincerity at the table is clearly in question, ... duplicitous.

I think the brand mark would be sincerity,

The egoism which enters into our theories does not affect their sincerity; rather, the more our egoism is satisfied, the more robust is our belief.

Enthusiasm is the genius of sincerity and truth accomplishes no victories without it.

Sincerity makes the very least person to be of more value than the most talented hypocrite.

How can sincerity be a condition of friendship? A taste for truth at any cost is a passion which spares nothing.