I looked back to your intro and found you are in the Philippines. It would be nice if you would change your profile so that shows; there are too many people coming and going for us to be able to remember all that.
Hopefully, imafan or one of our other tropical gardeners will come by and be able to ID your plant. I would just caution that just because something pops up as a volunteer does not mean it is native - many invasives are popping up all the time. But yours is very nice, whatever it is.