Post History

While emotions do show on the face and in the movement of the body, those are not the major ways that we judge people's emotions in real life. In particular, they are not the principle means by which we judge the intensity of the emotion. Different people, after all, vary hugely in how expressive they are of their emotions. Some are hugely demonstrative for no reason at all. Other are stoic through the direst of events.  

We judge emotion and the intensity of emotion chiefly by our knowledge of the history of the person up to the moment that the emotional trigger occurs. We expect that a person will have an emotional reaction based on our knowledge of what has happened to them, what we know them to be hoping for. 

If we know that someone has been waiting for an acceptance letter from Harvard, having spent every waking moment preparing and studying for the last ten years of their live, then if we see them go through the mail and pause on one envelope, our hearts immediately go into our mouths, and if we see them tear open the letter and read and then their face falls, we feel devastated. We know they are just heartbroken inside, even if the make little or no outward display of emotions beyond that first signal of disappointment. 

Note, though, that the intensity of our emotion is not based on the information alone. You can't just tell it in three sentences like I did above. (Which I presume did not bring a tear to your eye when you read them.) You have to follow the person, let us get to know and sympathize with them, let our hope and anticipation for their success build up. Only then will the revelation provoke the desired emotion. 

And remember too, that the job of the novelist is not to show emotion, it is to create emotion. Ultimately it is the emotions that the reader feels and projects onto the character that matter. Being told that the character has an emotion, being shown physical evidence of emotions, are cold and dead things if we are not feeling the emotions ourselves. 

To make the readers feel emotions, give your character a dream and crush it; give your character a lover and kill them; give your character a home and burn it to the ground. Do this and there is no need to show emotion. The reader will supply the emotion all by themselves. 

What then becomes interesting in the character's reaction is not that it tells us they are having the emotion, but that it allows us to calibrate the reaction against the emotion we have already projected onto them because we are feeling it ourselves. So where we have already projected profound emotion onto the character because of what we know about their history, we now observe their mild or concealed physical reaction and go Ah! They dare not show their feelings. And that introduces a new element of tension into your story, and that is good.