I bet you can't story. How can one respond to this statement?

You could say 'You're welcome. I'm glad you liked the story.' It's a simple and direct response.

Maybe it's because they don't understand the story well enough or have no clear thoughts about it.

It could be that there's some technical issue preventing you from responding. Or perhaps you're feeling intimidated and not confident in sharing your opinion.

Maybe you haven't registered or logged in properly. Make sure you have the right credentials.

You could say 'I'm so glad you feel that way.' It's a simple and positive response that shows you accept their declaration of love.

One could simply ask Frodo to explain further. For example, say 'Frodo, what exactly makes you think my life is a sad story?'. This way, you can get more details about his perspective.

Maybe they just don't have anything to say or don't know how to express their thoughts.

Well, it's a rather odd phrase. Maybe it's a misphrasing of 'I bet you can't tell a story'. If so, it's like a challenge daring someone to come up with a story. For example, in a group of friends, one might say this to another to see if they can be creative and share an interesting tale.

Maybe your internet connection is unstable. That could prevent you from responding.

Well, to respond to a long story, you need to be patient. Don't interrupt while the person is telling the story. When it's your turn to respond, you can share a relevant experience of your own. This shows that you can relate to what they've been through. Also, use positive language. Even if the story has some negative aspects, try to find something positive to say about it, like 'Despite the difficulties you faced in that story, it's amazing how you coped with it.'