It isn't useful as you get so many "rolls" on the Gossip chance, you don't need each roll to be 100% to have an effective 100% chance of locating Townhall Quests and Rumour Bosses.
For fun, assuming 6 each in Personality (30) and Awareness (15) is 45 Plus Gossip 3 (15) = 60
Rogue (+10 class bonus) plus Cowl/Hood (3), Trader Ring (6) = 19
Or Warrior/Cleric Items Cowl (3), Hero Shield (3), Trader Ring (6) = 12
So it's 79% Rogue or 72% Warrior/Cleric.
Pushing Personality to 10 adds another 20%, making 99% or 92%.
Meaning a Rogue needs Awareness 8 to hit 100% and a Warrior/Cleric needs Awareness 10.
Not that you will need it... at all... ever... except to amuse yourself, and perhaps amuse others.