Your friend may,however, warn you not to wear your heart on your sleeve.

VOA: special.2010.07.18

But I very... I've been told I wear my heart on my sleeve.

但我很……有人说我很直白。

幸福的定义 - SpeakingMax英语口语达人

When your heart is on your sleeve you are showing your deepest emotions.

VOA: special.2010.07.18

But I know that my father wears his heart on his sleeve.

VOA: special.2010.05.02