The most common and most likely answer to this crossword clue is the 8 letter word CREDIBLY
I've seen this crossword clue in Financial Times
C
R
E
D
I
B
L
Y
Buddy explains!
The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CREDIBLY mean?
CREDIBLY adverb- In a credible manner; believably.
- Used to report the speaker's assessment of the credibility of a reported statement