Guinness
Refers to the Irish beer brand or the company. Often used in contexts like Guinness beer or Guinness World Records.
I ordered a Guinness at the pub.
Gwyneth
A female given name, sometimes used in Japanese to refer to people like Gwyneth Paltrow. Less common than the beer brand sense.
Gwyneth Paltrow is sometimes written as ギネス.
He attempted the Guinness World Record for solving a Rubik's Cube the fastest.
The giant cake was registered in Guinness World Records.
I drank a real Guinness at an Irish pub.