Does Henry really believe all the stuff he tells Catherine at the end of chap 19 or is he just being careful of how he speaks about his increasingly-doubtful-brother to the innocent Catherine?

“…be as little uneasy as you can. You have no doubt of the mutual attachment of your brother and your friend; depend upon it, therefore, that real jealousy never can exist between them; depend upon it that no disagreement between them can be of any duration.”