Will my tummy tone up faster by doing sit ups with dumbbells

No. Not really.

There's a saying you should take to heart: "Abs are made in the kitchen."

The only real way to get abs is to get lean enough that they show through the layer of fat.

Also, sit ups are probably the worlds worst exercise for exercising the abs.


First, make sure your nutrition and calorie intake is in order.
Second, investigate things like planks (side, front, back, etc)
Third, after planks get easy investigate things like the "wheel of fun"

It may help you gain muscle faster, if that's what you mean. However if it remains hidden under belly fat you won't get to see it! And getting rid of the fat requires overall fat loss.

According to my physical trainer friend, there's lifting weights and wasting time! No such thing as toning!

Sit ups will strengthen your abs (and the added resistance of dumbbells will strengthen them further, provided you are using proper form), but no amount of sit ups will "tone" your stomach so that you can actually SEE your abs. Tone, in this context, is a noun, not a verb. It's not something you do; it's something you have. To get it, you have to burn fat, and there is no way to burn it from a specific part of your body.

As others have indicated, proper diet (lots of whole foods, not so much processed) and resistance training (namely heavy weights) are the best ways to get there.