The CS for CoP can be a bit long. Running joke was we do the CS for a fight and do the fight next week when the CS was over. I got the Sattva Ring. It's awesome for PLD with +hp, +vit and +agi. Everything a Paladin needs.
As far as emnity goes.... Every action you do generates hate or emnity. Once you do an action that gets you on the hate list of the mob, any other action will increase that hate. There's actually 2 types of hate and I could go on and on about some of the theories behind it. What you need to know is spike hate and how hate lowers over time. As I said, any action (including eating food) generates hate. Large hate tools or spike hate tools include provoke, flash, and cures. Hate fades over time. Usually at about the same rate that generated the hate. Meaning if all you did was Provoke a Mob and not other actions, that hate would be all gone by the time you were ready to Provoke again. Different actions lose hate at different rates. Usually, if it's spike hate, it goes away quickly, if it's not spike hate it fades slower. Hitting a mob creates a lot of hate and becomes cumulative because the hate doesn't fade as fast by the time you hit it again. You also lose hate when the mob does damage to you.
Emnity is the modifier for hate. Higher emnity allows larger hate spikes and longer hate "cool off" time. Meaning, if you have +emnity, your Provoke will gain more hate and last longer than just a regular provoke. The opposite is also true. If you have - emnity, your cures will spike less hate and fade quicker.
I tried to keep the explaination as simple as possible. Hope this helped. As a new minted PLD, hate is a big concern for you in party situations. The goal is to manage the hate to keep the party going. It doesn't do any good to be able to keep hate to the point you die because now everyone has to wait for you to get a raise and 5 more minutes to lose weakness. Everything is geared towards being efficient and allowing that War to take a couple hits on his shadows to save you some HP and the WHM some mp is part of the job.