Answer:
To adopt the culture of Western European countries - Westernize
To westernize simply means to change the culture of a country in order to make it seem more like the culture of Western European countries.
Belief that God created the monarchy to act as his representative - Divine right
The idea of the Divine right gave great power to monarchs, because they were seen almost as demi-gods.
A large fleet of warships - Armada
An armada is simply a large navy fleet.
High-ranking Russian nobility and landowner - Boyar
A Boyar was a high feudal lord who owned large sections of land. Boyars were also part of the nobility in Wallachia, Bulgaria, Serbia, and Moldavia.