must have , have to have , or should have , what should I use [closed]

You must have the physical and mental strength to accomplish whatever you want in sport

You can see the sentence above, I want to say. I want to say some fact, and want to express some obligation, that it must-have for achieving smth in sport, but as I see, construction must have used in different cases. According to this source we use it when we want to express believing that the action definitely happened. Can I use must have in my case, or it is used in the wrong way ?

Solution 1:

You are confusing the use of have as a main verb with its use as an auxiliary - part of a modal form. Your sentence is correct. Must is used as a modal whereas have is the main verb expressing possession.

This is not the case with must have used "to express believing that the action definitely happened". If you look at the examples given at the link you provide, must have is the past modal form of must, so have is not the main verb:

She must have left the house by now; it’s nearly 11 o'clock.

The main verb in this sentence is left, not have. Here "have" is only used to mark the fact that the action the speaker makes guesses or deductions about is a past action.