Amanda Knox is back in Italy for the first time since she was cleared of the murder of British student Meredith Kercher.
The 31-year-old American broke down in tears as she spoke about how she still fears new murder chargers.
Knox is in Italy to attend a panel discussing wrongful convictions.
Speaking to a crowd in the city of Modena, she said: "I'm afraid today, now, I'm afraid of being harassed, mocked, stuck and I'm afraid that new accusations will be addressed to me just because I come here to say my version of the facts.
"But above all, I fear I will lack the courage."
She said that, despite her acquittal, she knows she remains a controversial figure, especially in Italy.
"A lot of people think I'm crazy to come here. I was told that I was not safe, that I will be attacked in the streets, that I will be falsely accused and sent back to prison and that even if I return to Seattle, it will have been all in vain, it will not have been useful to anything," she said.
"On the world stage I wasn't a defendant innocent until proved guilty, the verdict fell upon me like a crushing weight."
Knox said she understood that Perugia prosecutor Giuliano Mignini wanted justice for murderer Kercher but said she hopes he will one day see she is not a monster. "I simply am Amanda."
The US woman spent four years in an Italian jail after being convicted, alongside her then-boyfriend Raffaele Sollecito, of the murder of the British student she lived with.
She said her family was only allowed to visit her for six one-hour sessions a month.
"At 20 years old I was a happy and a lively girl and I was forced to spend my 20th year imprisoned in an inhumane, unhealthy and unpredictable environment," she said.
"Instead of dreaming about a career or a family, I contemplated suicide."
She was acquitted in 2011, the first step in a long judicial process of flip-flop decisions, before being definitively acquitted in 2015 by Italy's highest court.
The lawyer for Meredith Kercher's family blasted Knox's return to Italy as "inappropriate".
He added "lawyers for both parties should have been involved".
A drifter called Rudy Guede was sentenced to 30 years in prison for the murder of Meredith.
Days before arriving in Italy, Knox made a bizarre Instagram posting, a picture on Instagram showing her clinging onto a mountainside with just her face visible.
"3 Days till I return to Italy for the first time since leaving prison. Feeling frayed, so I made my own inspirational workplace poster. 'Hang in there!' Just imagine I'm a kitten," she posted.
She also posted a photo of herself smiling in the arms of her fiance Christopher Robinson with the words: "Here we go … Wish us, "Buon viaggio!'".