The phrase 'proven reputation' is correct and usable in written English.
You can use it to refer to a reputation that is supported by evidence or proof. For example, "This company has a proven reputation for quality products and excellent customer service."
You definitely want a car insurer that's been in the business for a long period of time and that has a proven reputation.
"We need to improve our four-day performances quickly and Peter, with his vast experience and proven reputation as a coach, can help us do that," Newell said.
"Matthew has extensive coaching experience both in Australia and abroad and comes with a proven reputation," said Simmons.
Chairman Lee Thorn added: "He is the perfect candidate, with an outstanding proven reputation, and is the perfect fit for Nuneaton Town".
When Smith proposed marriage, Emma's father Isaac Hale objected because Smith was "a stranger" without a proven reputation and had no means of supporting his daughter other than money digging.
In 1918, Percival had been described as "a slim, soft spoken man... with a proven reputation for bravery and organisational powers" but by 1945 this description had been turned on its head with even Percival's defenders describing him as "something of a damp squib".
No jazz event could come close, but guitarist Pat Metheny proved his reputation outside the jazz loop, by performing alongside Latin-rock star Carlos Santana on the Philadelphia leg of the gigs.
Proving his reputation as one who makes an impression one on one, Brown won over Bryant in two meetings, the first in Orange County, where Bryant lives (and Brown has since bought a house), the second on the floor at the practice facility, going through plays.
Writing of Ford Madox Ford's hero Tietjens in Parade's End, who in the middle of a conversation suddenly wondered if he was in fact the father of his child but "proved his reputation for sanity" by going on talking without any sign of distress, Phillips comments: "As though sanity for this Englishman was about being apparently undisturbed by one's most disturbing thoughts".
I was watching the Olympic trials, being aired on very late-night cable USA Network (the broadcast didn't even begin until 11 PM), and Oregon track fans proved their reputation again.
Effectively dominating the Italian peninsula, and with a proven international military reputation, Rome now began to look to expand from the Italian mainland.
