A tourist struck a student on the head with a glass and dragged her down stairs by the hair in an attack in a well-known Dublin pub.
Sulinete Vieira (28) got an unfounded "notion" that the victim had "somehow slighted her" when she threw the glass and grabbed the woman, injuring her.
Judge John O'Leary gave her a one-month suspended sentence and ordered her to pay €1,000 in compensation.
Vieira, a cafe worker from Brazil but living in Lisbon, Portugal, pleaded guilty to assault.
Garda Sheamus Barry told Dublin District Court he was called to the Temple Bar Pub after 2am and spoke to the victim, who had a large swelling above her left eye and dark bruising to the side of her face.
The victim, a student in her 20s, said she had been trying to get money from an ATM in the pub when she was approached by Vieira. She asked Vieira to leave and the accused followed her up the stairs, where she threw a glass at her, hitting her.
She then dragged the victim down the steps by the hair. After her arrest, Vieira spent several days in custody.
Defence solicitor Michael O'Connor said Vieira had been here on holiday, went to the pub and got separated from her friends.
Vieira had some drink taken and "literally doesn't speak a word of English", he said.
She got "the notion there was some sort of disagreement" with the victim and that she had been "somewhat slighted".
She accepted there was "no factual basis for this" and the assault was unwarranted.
She apologised for her "appalling behaviour".
The victim wept as she gave evidence that she did nothing to provoke the accused.
"I don't understand how there could be a dispute, as all I said was: 'I'm sorry but I don't understand what you're saying to me'. She seemed quite off from the start," she said.
The victim said she was still nervous and anxious, adding: "I'm afraid to go out by myself."
Judge O'Leary said it was a very serious incident that had a "profound effect" on the victim who "suffered greatly" and was still distressed.