Truly

adv.kind, thoughtfuleveryday

Meaning 1

In a sincere or genuine manner.

Reach for it when emphasizing that a feeling, commitment, or quality is real

The guide truly cared whether every visitor understood the risk.

warm
sincerely
when honest feeling or intention matters
not when Sincerely is about the speaker's state, not whether a factual claim is correct.
warm
wholeheartedly
when complete commitment accompanies sincerity
not when Wholeheartedly is stronger and implies lack of reservation.
professional
genuinely
when authenticity rather than appearance is central
not when Genuinely can sound analytical and does not always convey personal sincerity.

In accordance with fact or accuracy.

Reach for it when stating that a claim matches reality

The design is truly accessible only if people can reach its controls independently.

everyday
really
when informal emphasis is all that is needed
not when Really is vague and can sound conversationally inflated.
professional
accurately
when correspondence to facts can be checked
not when Accurately concerns correctness, not genuineness or depth.
professional
actually
when correcting an assumption with fact is central
not when Actually can sound confrontational and does not imply sincerity.
literary
verily
when archaic or scriptural emphasis is deliberate
not when Verily is unsuitable for modern ordinary prose.

truly grateful
I am truly grateful for the correction before publication.
truly understand
We truly understand the process only when we can explain its failure modes.
truly remarkable
The result was truly remarkable because it held across all three sites.

The definition and the example on this page are written here. The dictionaries above ground which meaning is being described, not the wording.