For starters, I can feel it... don't you? But if you have any doubt go look an Anatomy book and it will show you how you need a beating heart to even write this question =)

Now your new account Young Rokr? It looks like an old man already Answering your question: Open your chest and take a look

as long i am breathing not unless theres a bullet in my chest its hard to Diggest. cowboy...

don't worry, you will always know it while you are still living and breathing. if it stops, you'll definitely won't have a chance to post this in italki: "hey, my heart stops beating!" good to see you on that bandana. :)

are you asking how you know that the heart is beating?