"Ella no muestra sus sentimientos."
Translation:She does not show her feelings.
No, it is a very common expression that means it is not easy to see if she is sad, happy, angry, etc.
Like my cousin....it is hard to tell if she is happy, mad, annoyed. It's just that she is quiet, and doesn't talk about or express her feelings easily.
I'd say 'very definitely' but it seems that written comments are not always the best medium for conveying sarcastic jokes :)
Sort of off topic, but, is there an expression that equates to "She has her heart on her sleeve." It's easy to see what she's feeling?
In real life spanish, that would usually be "Ella no muestra sus sentimientos."
The present tense is used for both the present and the present progressive, depending on the context.
"I'm going to the store" - Voy al mercado
The present progressive tense is used only for things happening IN THAT MOMENT, and is used with estar + the gerund.
Ella no está mostrando sus sentimientos.