...That's way too sad.

She just wanted to marry the person she loved.

Indeed.

But it was unrequited love. The Prince didn't love the Little Mermaid. It was one-sided.

Because of that misunderstanding.

If he'd known that princess wasn't his savior, he would've definitely loved the Little Mermaid back.

But when that didn't happen, she couldn't kill the person she loved.