Английский словарь американских идиом - wear one's heart on one's sleeve

also pin one's heart on one's sleeve {v. phr.} To show your feelings openly; show everyone how you feel; not hide your feelings. * /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./ Compare: OPEN ONE'S HEART.