으리라

'Surely will / must have'

-으리라 makes a confident prediction or supposition in an elevated voice, and here it usually leads straight into 믿다, 생각하다 or 예상하다: 책을 여러분들이 많이 읽으셨으리라 믿어 의심치 않는데 'I have no doubt you've read plenty of books.' It also stands alone as a vow — 그때는 지지 않으리라 'that time I will not lose.' It is the same ending as -리라, taking the 으 after a consonant.

Register: literary, formal speech