Terry Armer, 61, arrived midnight uninvited at the flat of Stacey Mackie armed with an axe, knives and a bottle of white spirit, it was said.
When she opened the door, he doused her with the accelerant and set her alight inside two minutes, a jury was told.
Stacey Mackie, 35, named Armer as her attacker to cops before she died the next day from burns to 90 per cent of her body, the court heard. Armer had tried to woo Stacey with flowers, gifts and by cooking her meals and inviting her to spend Christmas with him.
He sent a text saying “I love you to bits” and wanted her to be a Facebook friend, but she did not respond, the jury heard.
Prosecutor Tim Storrie said: “It appears he attached to their relationship an emotional significance that was not shared by Stacey.”
Armer saw red when Stacey called cops when he sent a “rambling and sexually abusive” text after his attempts to court her failed, it was said.
Armer, of Kendal, Cumbria, denies murder.