Answer:
I'm the source of all emotion, but I'm caged in a white prison.
Who has married hundreds but always been single?
Not a comb or a brush but makes the hair feel plush. What is it?
What has black spots and a white face, is fat not thin, and helps you to win, but tumbles all over the place?
What has fingers and a thumb but no hand?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.