1) say biopsy shows nodule is benign, fine, but how do i know this will not turn into malignant cancer in future ?

2) should i be repeating biopsy every month or what?

3) and can (numerous) biopsies get the nodule become malignant?

4) anyone whose biopsy detected benign nodule but this ended up being malignant cancer after some time?

benign can become cancerous if its not treated or removed

i dont think you would need a biopsy every month.

usually when you have a biopsy, hopefully it wont return, and when it does you can have another surgery to remove it, unless it spreads to body and become cancer

if benign keeps returning its more like cancer