This is the 10442nd most frequent Russian word.
вернут
"Вернут" means "will return" in English.
In this sentence, "вернут" is used as the 3rd person plural future tense of the verb "вернуть," meaning to return something to its rightful place.
Они вернут книгу завтра.
They will return the book tomorrow.
Here, "вернёт" is used in the singular 3rd person future tense, referring to someone repaying or returning owed money.
Когда он вернёт долг?
When will he return the debt?
This illustrates the 1st person plural future tense usage of "вернём," indicating an action the speakers themselves will undertake.