The most common and most likely answer to this crossword clue is the 8 letter word GEE-GEES
I've seen this crossword clue in The Guardian
G
E
E
-
G
E
E
S
More clues leading to the result GEE-GEES
Buddy explains!
The straight part
We know that "which you can bet on" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case which you can bet on = gee-gees.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 GEE-GEES mean?
GEE-GEES noun- (usually childish) A horse.
- (usually with 'the') horse racing.