The Two Sentences That Doubled My Trial Conversion

I changed two sentences on my signup page. Not the design, not the pricing, not the flow. Two sentences.

Trial to paid conversion went from 9% to 18% in three weeks.

The original sentences explained what the product does. The new ones explained what the person would have five minutes after signing up. Same product. Different promise. One was about me. The other was about them.

I had been describing features when I should have been describing the moment after.

What's the smallest copy change that made the biggest difference for you?