Rewrite this sentence to make it more concise: The thing is, the reason why she's unhappy is that she believes nobody loves her.
She's unhappy because she believes nobody loves her.
Complete the following task based on the instruction and optional input provided.### Instruction:
Rewrite this sentence to make it more concise: The thing is, the reason why she's unhappy is that she believes nobody loves her.

### Output:
She's unhappy because she believes nobody loves her.