The most common and most likely answer to this crossword clue is the 10 letter word ELOQUENTLY
I've seen this crossword clue in The Guardian
E
L
O
Q
U
E
N
T
L
Y
Buddy explains!
The straight part
We know that "speaks in a spell-binding way" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case speaks in a spell-binding way = eloquently.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 ELOQUENTLY mean?
ELOQUENTLY adverb- In an eloquent manner; stated well.