Which flowering plant?

[S.Ahmed]

I have this one's full grown plant at my other place, I had been attempting to propagate it by simply cutting stem from mother plant and planting it in pot,but that doesn't seem to be working and potted plant starts drying up within a week.

Any one know its name and how should I be propagating it?

[Izhar]

Tabernaemontana divaricata "flore pleno"