What job is the noun clause doing in this sentence Your great dream that people will truly love one another?

The noun clause "that people will truly love one another" is acting as the object of the preposition "of".

Here's why:

* The sentence is incomplete without the noun clause.

* The noun clause is acting as the object of the preposition "of" to complete the phrase "Your great dream of..."

* The entire phrase "Your great dream of that people will truly love one another" functions as a noun phrase.

Let me know if you'd like more examples or have any further questions!