Hiya and the best words I could find are these which you can locate if you do a search for an English-Swahili dictionary.
Mheshimiwa noun 1/2
Honourable, Excellency
Mhe. abbreviation See Mheshimiwa
► Mhe. Spika na mkewe the Honourable Spika and his wife
Waheshimiwa pl noun 1/2 See singular Mheshimiwa
mtukufu noun 1/2
1 his excellency, his highness, his majesty
2 exalted person
3 respected person, important person
watukufu pl noun 1/2 See singular mtukufu
1 exalted people
2 their highnesses
3 their majesties
4 their excellencies
I just wondered how and where you would use this as there are not many Monarchs or Royal persons in the Swahili language area. I am intrigued and ready to be corrected.
If you were thinking in a prayerful way then Mungu Mtukufu would be very appropriate.
