"Forgive my verbosity"

I heard a text in English read out loud the other day. It was a translation from Russian of a letter a man had written in response to an existential question addressed to him by letter by his sister. The man answered very nobly and respectfully, at length. Before finishing the letter I heard this sentence:

Forgive my verbosity.

It struck me as pretentious in the context. Is it just my idea? The letter was written in the 1950’s, so I will grant the translator that a certain register of language must be used. However, checking the original Russian, I found that the words used for this sentence were much warmer and less pretentious, with a humble self-irony but also expressing affection towards his sister.

My question is, are there any other sentences that can express this in a way that is appropriate with the period, the affection between the brother and the sister, and the non-pretentiousness?

Note 1: The author of the letter was well educated.

Note 2: I have nothing against Forgive my, I find it rather elegant and appropriate. What bothered me was verbosity.