Meaning of “truly” - Learner’s Dictionary

truly

adverb uk us /ˈtruːli/
NOT FALSE

used to emphasize that something is true in every way:

The project was truly a team effort.
VERY

B2 used to emphasize a description of something:

It's truly amazing to watch a baby being born.
SINCERE

used to emphasize that something is sincere or honest:

I truly believe that he is innocent.

(Definition of “truly” from the Cambridge Learner’s Dictionary © Cambridge University Press)