broken heart       
noun [ C ] uk/ˌbrəʊ.kən ˈhɑː.t/ us/ˌbroʊ.kən ˈhɑːrt/
 心碎
a feeling of great sadness, especially when someone you love dies or does not love you
  They say he died of a broken heart. 他们说他死于心碎。 
 I was unhappy and trying to mend/heal my broken heart.  我很不高兴,想治愈自己那颗破碎的心。 
 See: broken-hearted
 - More examples
 - She has a broken heart - her husband died six months ago.
 - Broken hearts are as much a part of our lives as falling in love.
 - The quiet countryside is a place for tired minds to recharge and broken hearts to mend.
 - It takes years, maybe a lifetime, to heal a broken heart.