Interesting expression in an anime that I can find only there and there is no information on the internet, that I can find, about its origin&history

Question

In the Anime Honzuki no Gekokujo season 2, episode 4 from 19:56 onward the main protagonist says "Arigatou Gozaimasu", to thank the high priest and is immediately corrected by him with something that, at least I hear as - "Arigatou Zongdzi-masu".

After extensive search on the internet and discussions with at least two people that speak Japanese, at various levels, I found that there is no such phrase in Japanese, yet I still hear it in a Japanese anime, voiced by Japanese actors...

I found that Zongdzi is a rice dumpling, searched for all words and expressions that can end on "masu"(and since this is a polite ending there are a lot of them), checked in few online Japanese-English dictionaries but couldn't find anything.

In the English subtitles version it was translated as "Please accept my deepest gratitude" and was specified that this is a way for a noble women to thank for something. I searched the web for a direct translation of the quoted phrase in Japanese and found quite a few of those, but nothing that is even remotely close to what I hear.

Please, if possible, can someone share what the phrase said in the anime should look like, written in English, I am suspecting it is not Zongdzimasu, and if it wont be a lot of additional work the phrase history and applications.

Answer 1

The man in the video says ありがとう存じます, where 存ずる【ぞんずる】 is a humble verb for 考える. You may have heard (～と)存じ上げます, which is more common.

That said, ありがとう存じます is not something usually said by real modern Japanese speakers (including "upper class" speakers). When something more stilted than ありがとうございます is necessary, people usually say 感謝申し上げます, ありがたく存じます, etc. There is usually nothing wrong with the girl saying ありがとうございます in this situation, so I feel this scene is meant to emphasize the weirdness of 貴族言葉 in this world.

(EDIT: Looks like there are several native Japanese speakers who are wondering if ありがとう存じます used in this anime is a real phrase. In my opinion, it might have been a valid expression 150 years ago when ウ音便 as in 悲しゅうありません and 嬉しゅうて喜ばしゅうて was a norm among upper-class ladies, but it's unnatural at least in today's standard Japanese.)

Japanese has no sound that is romanized as "dzi", so you can get almost nothing related to Japanese by searching with this spelling. What you heard is just one of the allophones of じ ("ji" in Hepburn romanization, "zi" in kunrei). See: "z" sound, which to choose?