The weakest part of a bike are the wheels, it is unheard of for a frame to snap because of weight.
A std spoked wheel can be made stronger by having more spokes (36 rather than 32), correct and even spoke tension and well trued.
Factory bikes often come with machine-built wheels which are not as well built as they could be.
A good local bike shop (LBS) should be able to tune up the wheel to make it a lot stronger. This is worthwhile even on entry-level bikes and is one of the best reasons to use a good LBS rather than a box-shifter, generic sports shop or online bargain.

Non sus MTBs of any quality are becoming rare. Jamis still make one which is OK, I think it is called the Ranger.