" So, Jessamine,” said Lucie. “Can ghosts lie?”
“Certainly not!” Jessamine looked shifty. “Ghosts are completely honest. I keep telling you, it was mice who knocked your silver mirror behind the desk and broke it.”
“It appears clear that if ghosts are liars, they are terrible liars,” said James.
Matthew sighed. “It is very strange to see you conversing with the invisible.”
“Humph,” said Jessamine. She wobbled a bit and firmed up, her outlines clearing as she drifted down toward the floor. Shadowhunters, having the Sight, could generally see ghosts who wanted to be seen, but Lucie knew it was an effort for Jessamine to make herself visible to all eyes.
“Oh!” said Cordelia. “It’s very nice to meet you, Jessamine. Lucie speaks of you often.”
Jessamine beamed.
“You are a very attractive ghost,” said Matthew, tapping his ringed fingers against his chest. “I do hope Lucie and James have mentioned as much.”
“They have not,” Jessamine noted.
“Very remiss,” said Matthew, his eyes sparkling.
“You are not at all like Henry,” said Jessamine, eyeing Matthew speculatively. “He was forever setting things on fire, and not a compliment to be heard.”
“Jessamine,” Lucie said. “This is important! Do tell us, can ghosts lie? Not you, of course, my dear.”
“Ghosts can lie,” Jessamine conceded. "

― Cassandra Clare , Chain of Gold (The Last Hours, #1)