I am not sure whether to use 'insisted on' or 'insisted to' in the above sentence. Which one is grammatically correct?
She insisted me to post this one.
She insisted on posting this one.
The correct grammar is "She insisted on posting this one."
This means that she insisted that she post this one.
If you intend to convey that she insisted that you post this one, you would say.
She insisted I post this one. -or- She insisted that I post this one.
Neither of those is really correct for what you're trying to say. "She insisted on posting this one" would imply that she is posting it no matter what your opinion is.
If she is trying to convince you to do it, the correct phrasing would be, "She insisted that I post this one."
Some Americans would say "She insisted on me posting this one", but that's not quite grammatical.