Your good news hurt them, your hardship pleased them.
Watch what you feel at others' news
The hypocrites were upset when the Prophet ﷺ and his companions had victory, and when hardship came they said, we took our precautions by staying out of it, and turned away pleased. Ibn Kathir calls it the depth of their enmity.
Your cousin's business takes off and something sour rises in you. A colleague fails and you feel a tiny glow of "told you so." Catch that feeling. It is the exact reaction this verse describes.
A little satisfaction when others fail is only human.
Being glad at a believer's hardship is a sign to heal my heart.
Congratulate, sincerely, someone whose success you felt a pang about.