So let's look at your initial concept and answer the following questions:

What is your story about, in ONE sentence (we've given you that) - 

This is what you want your audience to understand at the end of the film ('Love is shown more in deeds than words').

Then...

What is your story about, in ONE word? - 

This is your story’s THEME.

Let's look at an example:

Harder

Premise:

Tom (15) sleeps in school. At night he avoids the violent contrasts of his Mother’s (31) love-life by hiding in neighbouring gardens. But with Mum pregnant how can Tom stop her brutal lover’s cycle of abuse? Short Contemporary Horror.

A one sentence version of the premise is:

Self absorption leads to the annihilation of love.

Theme, in one word:

Betrayal

Identifying that the THEME of Harder was 'Betrayal' was helpful because it meant that I could work everything in the script towards supporting the audience's final realisation that (in this story) it is the mother's 'self absorption' that leads to the annihilation of love, both in the death of the man that she 'loves' and in the psychological breakdown of the child she was supposed to love.

In this story the mother's self absorption, her focus away from her son and towards her own emotional needs is a BETRAYAL of the bond between a mother and her child.

I could use the relationship between the boy and his friend to illustrate what the boy is looking for - love.

I could then illustrate love being denied him by his mother in a range of ways, always counterpointed by her focus away from him and towards her abusive lover.

The key point (CORE) in the film is not the destruction of the man by the boy, but following such an extreme demonstration of his desire to protect his mother and his scream for her affection, it is the way in which the mother STILL denies her child as he reaches out for her. 

The betrayal of the bond between mother and child is reenforced.