I want to ask why our Holy Prophet (Peace be Upon Him) gave death order of Asma Bint Marwan?
The Prophet never did order the killing of Asma bint Marwan. The story is fabricated. The chain of narrators (isnad) is very weak, including one narrator who was known to be a liar (Muhammad ibn Ibrahim ibn al-Ala al-Schami).
Many Western historians pointed to this tale in order to belittle the Prophet and show Islam in a negative light.