Question

I need help with a thesis sentence..
The narrator in The Daughter Leaving Home is sad, honored, and betrayed because her daughter is becoming a greater person in the world.

Answer 1

1. You have three complements that all show emotion: sad, honored, and betrayed; so you want a verb that expresses emotion. You could change "is" to "feels" or a similar verb:
"The narrator in The Daughter Leaving Home feels sad, honored, and betrayed, because her daughter is becoming a greater person in the world."

2. The verb "becoming" is a continuing action in the present. To give your reader a little more information on the changing relationship between these two people, you could add a time modifier to the verb on the main clause:
"The narrator in The Daughter Leaving Home begins to feel sad, honored, and betrayed, because her daughter is becoming a greater person in the world."

3. Your sentence is declarative and straightforward: subject - verb - restrictive clause. You could mix it up a little to add interest. This will also have the effect of controlling the reader's sympathy, by ending the sentence on how the narrator feels, instead of on what the daughter has done:
"Because her daughter is becoming a greater person in the world, the narrator in The Daughter Leaving Home begins to feel sad, honored, and betrayed."

With these changes, the reader first meets the daughter and learns that she is improving her life. Then the reader meets the mother / narrator and is drawn in to her emotions. Try it: you cannot read the phrase "feel ..." without feeling something yourself; it's a gut reaction. Finally the reader is left with the mixed negative and positive of "sad, honored, and betrayed", and is ready to hear what you think about the story.