Health is our greatest wealth.
>> CORRECT

Because there is not much we can achieve if we are not healthy.
>> There is not much we can achieve if we are not healthy.

This is true of both mental and physical health.
>> CORRECT

Planning is important to achieve something.
>> Planning is important in achieving something.

If you are mentally unhealthy, you will set the wrong plan and direction.
>> If you are mentally unhealthy, you may set the wrong plan and direction.

This could be the case for everyone.
>> CORRECT

Even if you set the right direction and plan, it is very difficult to proceed with the work on your own if you are physically unhealthy.
>> Even if you set the right direction and plan, it can be very difficult to proceed with work on your own if you are physically unhealthy.

Of course, you can do it with the help of others, but there are many difficulties.
>> Of course, you can do it with the help of others, but it may come with many difficulties.

Today's wealth is evaluated by the possession of money, but if you are unhealthy, it is difficult to maintain wealth.
>> Wealth today is often measured by the possession of money, but if you are unhealthy, it can be difficult to maintain it.

If you are healthy, you have the potential to achieve anything, so you are a person of true wealth.
>> If you are healthy, you have the potential to achieve anything and are truly wealthy.