Nicholas William Goss (38) has admitted killing Michelle de Gruchy Gibson, a former air stewardess, at her flat in Cannon Street on Saturday 22 May last year.
When Goss appears in the Royal Court for sentencing, he will receive a mandatory life sentence but it will be up to the court to set the minimum term he must serve.
He killed his former lover after she had been out for the evening on Friday 21 May.
Goss was on the run for two days.
He fled to France but responded to pleas from the police to return to the Island, and was arrested back in Jersey on 24 May at around 6.30 pm.
