A man dressed in a sarong and an Israeli flag scrawled the word "delusional" in permanent marker on a frightened woman's front door, a court heard.
The victim phoned the gardaí when she looked outside to see the graffiti and Alan O'Brien (49) walking in circles, calling her name, a court heard.
O'Brien had "preached the gospel with her" before and decided to get in touch with the woman again in a "very unorthodox way".
Judge Colin Daly put him on a bond to keep the peace and be of good behaviour for a year on condition he stays away from the victim.
O'Brien, of St Patrick's Square, Newbridge, Co Kildare, pleaded guilty to criminal damage to the woman's door.
Garda Michael Cleary told Dublin District Court he took a report of damage at the victim's home in Drimnagh last September 12.
The accused had written in permanent marker on her front door "love and truth" and the woman's name, as well as the word "delusional", in inverted commas. It cost €50 to have the graffiti removed.
The accused had been wearing an Israeli flag, an LGBT flag and a blue sarong, the garda said. He had 25 previous convictions for offences including assault.
Defence barrister Rory Mulvaney said of his client it was "very clear he was going through an episode at the time".
Not long after the incident, the accused was hospitalised for mental health difficulties.
He apologised to the victim and was prepared to pay compensation, Mr Mulvaney said.
O'Brien, who had lived in the area, suffered from bipolar disorder and was "in the throes of serious mental health difficulties" at the time of the offence, the court heard.
He was "in the height of it" at the time and could not fully explain his behaviour.
He was attempting to reconnect with the victim and "went about it in a very unorthodox way". O'Brien was now "back down to earth" and "much more on the level", Mr Mulvaney said.
In her victim impact statement, the woman said she heard a noise at her front door at about 7am and thought it might be "the insulation man".
She looked out and saw O'Brien, who said: "I told you I was serious about this." When she told him to go, he said: "I heard you had a heart attack."
He was outside her house going around in a circle, calling her name.
The court heard that the victim knew O'Brien previously and he had "preached the gospel with her".
She had been in hospital for a serious heart operation and felt "stressed, worried and afraid".
"When I saw the writing I went, 'Oh my God'," she said.
The woman said she forgave O'Brien, but "I just want him to leave me in peace".
She told the court she did not want any compensation.
Binding him to the peace on condition he stays away from the victim, Judge Daly also ordered the accused to pay €50 to a homeless charity.