wear one's heart on one's sleeve

Cultural  

1. To express affection or sentiment too openly or ostentatiously: “You have to play it cool with a girl like Heidi; you mustn't wear your heart on your sleeve.”

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wear one's heart on one's sleeve Idioms  

1. Also, pin one's heart on one's sleeve. Openly show one's feelings, especially amorous ones. For example, You can't help but see how he feels about her; he wears his heart on his sleeve. This expression alludes to the former custom of tying a woman's favor to her lover's sleeve, thereby announcing their attachment. Shakespeare had it in Othello (1:1): “But I will wear my heart upon my sleeve for daws to peck at.”

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Example Sentences

When trying to establish a relationship is it better to play hard to get or is it better to wear one’s heart on one’s sleeve?

From Scientific American

As for honor, I laugh at most of the things I believe in, just because it's the fashion of the day—and I belong to the day I live in—not to wear one's heart on one's sleeve.

From Project Gutenberg