There is no confirmed girlfriend for Levi in Attack on Titan. That said, it doesn’t stop the fan base from trying to ship him with plenty of people. One of the most notable ones is Petra, a member of his squad that he seemingly cared about. I find that Isabel is a more compelling romantic partner as the girl he grew up with. It’s possible that her (spoiler alert) death before the start of the series is the main reason we don’t see him connect romantically with anyone.