No need to apologise, that's what we're here for, to help!
I usually go with what I think is the most accurate temperature. At times, I keep two or three temperature monitoring programs open. Core Temp, Real Temp, AI Suite II, and HWMonitor. Though, I tend to stick with HWMonitor's readings due to using this program for ages+I feel it's the most accurate.
Generally speaking, any software that tells you CPU temperatures will be off by a few degrees, none are 100% accurate. For the most accurate temperatures, you should go inside your BIOS