wear one's heart on one's sleeve

wear one's heart on one's sleeve также pin one's heart on one's sleeve  {v. phr.}

Открыто проявлять свои чувства; давать волю чувствам; не скрывать чувств.

She wears her heart on her sleeve. It's easy to see if she is sad or happy.

Sometimes it is better not to pin your heart on your sleeve.

Ср.: OPEN ONE'S HEART.