"Have you known me not to be serious?"

He's got the suspicion that Harrow is patronizing him now. Han may be naive to the ways of magic, but being put down is old hat for him. It's just ... so damn hard for him to wrap his head around a guy coming back to life. There ain't none of that where he's from - and if there is, screw everybody he loved that died on him and then didn't come back to visit.

Till he sees the guy acting really undeadish, he remains skeptical.