The most common and most likely answer to this crossword clue is the 8 letter word RESOLUTE
I've seen this crossword clue in The Guardian
R
E
S
O
L
U
T
E
More clues leading to the result RESOLUTE
- Decided to repair bottom of shoe split by tips of umpteen tacks
- Our steel tempered and unyielding
- Determined work on footwear, extremely urgent, inside
- Determined to give poor Rose an instrument
- Firm, with failure coming up, pretty short of cents
- Persistent roués let off
- Decided about well before money is mentioned
- Intent on rendering two notes on an instrument
- Firm that’s manufactured our steel
- Unwavering English group of workers, one not winning after setback
Buddy explains!

The straight part
We know that "Decided" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case decided = resolute.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 RESOLUTE mean?
RESOLUTE noun- A determined person; one showing resolution.
- Firm, unyielding, determined.
- Convinced; satisfied; sure.