It's the highest compliment to be paid. If you tell me I'm attractive, funny, or a good listener my response is likely a lackluster, "Gee, thanks." Tell me I'm smart and I'll likely cry from sheer joy. Smart has to be proven, smart is fluid, smart takes you places! Unless of course smart is used in the context of fashion: "Boy that's a smart blazer you've got on there!" Then it's less of a big deal.
It's overly dramatic in any context I can imagine. "My heart is broken!" Ugh. "You gotta have heart!" Ugh. "My heart beats only for you!" Ugh! Ugh! Dial down the drama and find a better, more intelligent sounding word.