The most common and most likely answer to this crossword clue is the 8 letter word HALLMARK
H
A
L
L
M
A
R
K
More clues leading to the result HALLMARK
- Everything in hot gospel is a sign of quality
- Stamp from Hong Kong having left in false alarm
- Sign of saint buried under lobby
- Distinguishing feature of hotel brand accommodating everybody
- Hard book — after all, that’s an indication of quality
- Finally Noah with ship taking on board disheartened woolly animal producing guarantee of pedigree
- Hard gospel for everyone to penetrate — a distinctive feature
- Distinctive quality of Jerry and Nick
Buddy explains!

The straight part
We know that "guarantee of pedigree" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case guarantee of pedigree = hallmark.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 HALLMARK mean?
HALLMARK noun- A distinguishing characteristic.
- An official marking made by a trusted party, usually an assay office, on items made of precious metals.
- To provide or stamp with a hallmark.