Faithfully

Common synonyms include: absolutely, accurately, acquiescently, assiduously, authentically, bona fide.

/ˈfeɪθfəli/ adv

adv ·Moderate ·College level

Definitions

Adverb

1
In a faithful manner.
"The CD reproduces music faithfully."
2
A conventional formula for ending a letter, used when the salutation addresses the person for whom the letter is intended using an honorific. US

Adverb

"Take this medicine faithfully, and you will feel better."

From Middle English feithfulli, equivalent to faithful + -ly.