What is the noun clause in the sentence: "My great dream is that people will truly love one another."?
"That people will truly love one another."
Noun clauses are introduced by words such as that (as it is in this case), when, what, how, where, whatever, which, whether, whoever, whom, etc.
Noun clauses include a subject (people) and a verb (will love).
All of the words act together as a noun.
A helpful site with lots of examples: