This is the 2696th most frequent Russian word.
астане
"Астане" is the prepositional case of "Астана," referring to "Astana," the former name of the capital of Kazakhstan, now called Nur-Sultan.
This usage of 'Астане' refers to the city of Astana, Kazakhstan, in the prepositional case, which is used after the preposition 'в' to denote location.
Я живу в Астане.
I live in Astana.
In this sentence, 'Астане' is used in the prepositional case to indicate where the meeting will take place.
Мы будем встречаться в Астане завтра.
We will meet in Astana tomorrow.
Here, the word 'Астану' is in the accusative case ('Астане' would not be applicable), as it indicates the destination of the trip, differing from the previous usage.