懂

Why does 懂 look like this?

The character features the heart radical (忄) on the left, which tells us it's related to feelings or mental processes. On the right is '重' (zhòng/dǒng), which originally depicted an eye looking at a bag/container, but here it acts as a phonetic component. Together, it represents the heart 'grasping' or 'weighing' the meaning of something.