"Love Jihad" is a communal conspiracy theory floated by Hindutva groups and used to attack Hindu-Muslim couples. According to Sangh Parivar organisations such as the Hindu Rakshak Samiti (HRS), the Hindu Janajagruti Samiti and the Sri Ram Sene, Muslim men lure Hindu women into marriage with the aim of increasing the Muslim population. The term has been used to mobilise Hindutva forces to violence, most notably in the Muzaffarnagar communal violence.
References:
• The Sexual Politics of Modi, the BJP and the Sangh Parivar.
Love Jihad: From illusory slogan to dangerous weapon.