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general::
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."
American Heritage Idioms