I got one for Christmas. No enamel inside. Can I use it for cheese or chocolate fondue, or just for hot oil to cook meats? Anyone experienced in this?

I think it is quite safe to cook and eat out of iron pots. Some food may discolour the metal (try a little vinagar and salt to clean them). Don't store left overs in a metal cooking pot, transfer them to a clean ceramic/glass/plastic container.
Cheers and happy cooking...ahhh fondue, now that brings back memories