In a small mixing bowl, mix together the sliced strawberries and sugar. Then cover and set aside for at least 20 minutes to macerate; any longer, and they'll need to macerate in the fridge instead of on the counter.
Once the strawberries have fully macerated for 20 minutes or longer, strain the juices from the berries into a separate bowl. I recommend using a rubber spatula to really swish the strawberries around, in order to gently squeeze any juice you can from the berry mixture. Then let the berries sit in the strainer over the bowl to drip while completing the next step.
In a separate large bowl or container, whisk together the Jello mix and boiling water, stirring for 2 minutes 'til the Jello mix is completely dissolved.
Pour the strawberry juice into a 2-cup measuring cup, scraping the sides of the bowl to get any juice/sugar left on the sides of the bowl. Then finish filling with cold water to the 2-cup mark.
Stir the strawberry juice/cold water mixture into the Jello, stirring 'til blended well.
Finally, stir the strawberries into the Jello.
Cover and chill for at least 4 hours, longer if possible.
It's ready to serve when the Jello is set; this Jello will be slightly soft set but firm. Makes a fantastic family favorite side dish at any special gathering.