If it was really Latin that you saw, then it might have been:
Surge aut sis eques in nomine Dei 1
Stand up as a knight, in the name of God.
This is how William Camden described the ancient ceremony in his Britannia. There are variations, such as substituting
aut. I'd be a bit surprised if the site you originally found actually used Latin, though.
Since you expected to find the answer in English ("I dub thee"), I suppose the question is focused on England. In that case, as @SteveBird's rightly points out, the traditional words are in French, not Latin. Complementing his answer, the classical formula is for the sovereign to lay a naked blade on the candidate's left shoulder and pronounce:
Sois chevalier, au nom de Dieu 2
(Be thou a knight in the name of God)
Followed by the command to rise:
Avancez chevalier 2
The use of French has long since died out in English governance. In later times, it appears the monarch simply pronounce:
Rise up, Sir (name) 3
This part is possibly slightly profane. Mouseover to show.
Jake Cade: Rise up, Sir Dick Butcher
- William Shakespeare, 3 Henry VI (certain versions).
 Jacob, Giles, and Thomas Edlyne Tomlins. The Law-Dictionary: Explaining the Rise, Progress, and Present State, of the English Law. A. Strahan, Law Printer to the King's Most Excellent Majesty, 1809.
 Burke, John Bernard. The Knightage of Great Britain and Ireland. London: Edward Churton, 1841.
 Cox, Thomas, and William Camden. Magna Britannia et Hibernia, Antiqua & Nova Or, A New Survey of Great Britain. Savoy: Nutt and Morphew, 1720.