Narayana vs. Naaraayan'
Meaning
Personification of the Supreme Soul, personal God. Naaraayan' means goal of every individual soul.
Shri Krishn' is His Avataar, who delivered the message of BhagavadGita to Arjun' at KuruKshetr'.
Pronunciation
If you would want to pronounce it, looking at the spelling Naaraayan', you are likely to come relatively closer to how it is written नारायण and pronounced in Sanskrit, using its original Dev'Naagari script. Last N in Naaraayan is supposed to be pronounced with a hard tone, but there is no English equivalent and therefore, it is hard to describe in writing as to how exactly it should be pronounced.
With the knowledge of this limitation, you may want to pronounce both N in Naaraayan as is N normally pronounced in English. This difficulty arises because we have half the number of vowels and consonants in English as compared to Sanskrit. In Sanskrit alphabet, you find a different letter for conceivably each and every kind of intonation, which could be fundamentally essential, for producing any vocal sound for expression of any human language.
You may, however, choose to follow spelling Narayana, and practice its pronunciation with a wrong accent नारायणा. The choice would be entirely yours!