Hey Bruno Mars, grenades aside, in what possible scenario are you going to walk in front of a train for someone you love? I mean, even if you had to save the person you love from some kind of super-villain, you'd probably run in front of the train. And if the person you love actually asked you to walk in front of the train to prove your love, they're not the one for you in the first place.

I guess it sounds more extreme than promising something like "I'd wait for five hours at the doctor's office with you." or "I'd follow you into twenty-five different shoe stores for an entire day" or "I'd spend an awkward afternoon at a baby shower for you."

It's probably better to say you would do something for a circumstance that would never arise anyways.