wear your heart on your sleeve 感情外露；坦露心情；告诉别人你的感受；流露自己的感情

【例句】
Mary is one of those people who wears her heart on her sleeve.
Mary是那种感情外露的人。

Jane simply doesn't wear her heart of sleeve so it's sometimes difficult to know what she is feeling.
Jane不表露自己的情绪，所以有时候很难知道她的感受。