Alright, before anyone can get confused here, let me tell you one thing: Freyja has been SLIGHTLY changed. If you read the whole Norse Mythology you will understand that plenty of the things I wrote here are actually true. These are the only things I changed:
-She is not a Giantess (although the Gods are naturally taller than Humans) in the official stories.
-Her necklace does not contain her powers in any way, it's just a necklace, even if Odin wanted it stolen once and sent Loki to do it in the shape of a seal, most likely when the war between the Aesir and the Vanir was still going on. The idea of giving it a restraining power came from one of the stories... And that you will experience soon.
-The reasons why Freyja hates Loki are plenty more and involve even the failed attempt of stealing her Necklace.
That's it.
All the rest is absolutely pure truth, straight from the Norse Mythology, including the fact that she receives 50% of the souls that are supposed to go to Valhalla.