What does it mean?

[lovejoy]

He/she wears their heart on their sleeve. What exactly does this mean?

[lankeela]

Don't know where it comes from but it means you clearly show your feelings for someone. In other words, everyone knows you are in love with someone.

[Ethel]

http://www.phrases.org.uk/meanings/403000.html

[lovejoy]

Thanks to both of you

[VS Prasad]

- Display one's emotions openly.

They are walking down the street with "their hearts in their hands".

HEART ON YOUR SLEEVE - : IAGO:
It is sure as you are Roderigo,
Were I the Moor, I would not be Iago.....

http://www.phrases.org.uk/bulletin_board/54/me ssages/27.html