Hi I'm use to play The Sims 2 but as I now own a better laptop I thought of trying TheSims 3. But can it run it?

Spec:

Brand/model: Dell Latitude E6430
OS: Win 10
CPU: Intel Core i5 3340M
Ram: 8GiB DDR3
Chip: Intel HD Graphics 4000

It might turn on but it probably won't run well. Try to aim for something that has an Nvidia GTX 1050 or better.

Hm Ok, then I can do other things on this computer instead (I bought it because I needed a better laptop).

A GTX1050 is way overkill!
I ran this game pretty well on a GT610 and can also run it decently on my integrated ATI Radeon 3000 Graphics.
A GTX1050 is good for heavy gaming, but that above recommended on most games I have seen, meaning you can use something far less than that and still run perfectly.
Laptops, however, especially Dell, are not good for gaming at all, but in the case of Sims3, it should run it decently, provided the user knows how to optimize more than EA can.