All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
After much research, we could not find a Fatwa issued by any of the Imaams of the Holy Mosque in Makkah in this regard. Specialists, after studying the origin of the word in English, concluded that there is no connection between the word "Hell" and "Hello" which is used to call someone from a distance to draw their attention or the like.
However, the word "Hello" should not be used as a greeting, since the greeting of Islam is "Assalamu alaykum". Salam should not be substituted by any other greeting even if it is an Arabic greeting, let alone a greeting in foreign languages. We previously clarified this point in Fataawa 89959, 83047 and 83956. For further benefit, see Fatwa 119027.