Castle Crasher and Castle Raid are solo missions that each give +225 points. Doing any combo of 2 of these gets you from dubious to apprehensive. Castle Growth is of no use for this purpose since it requires being apprehensive already in order to obtain the mission.
I doubt you can kill Priestess Glihelin since she's a quest NPC. Can't say I've tried tho...
Edited, Feb 19th 2015 2:29pm by Sippin