Is it right correct?

The worst of the passion is the end, when the end's endpoint is not followed by two suspension points.

The second the would be optional. If you are trying to sound poetic, I would remove it because of redundancy. It is sufficient, and more aesthetically sound to say "The worst of passion is the end." However, another problem occurs here because that is a full sentence. 

and then you folow it with a dependent clause, but it can't stand alone "When the end's endpoint is not followed by two suspension points"

so my corrected sentence would read "The worst of passion lies within the end, especially when the endpoint is not followed by two suspension points." 

However, if you are not trying to be poetic, this statement  of an endpoint with two suspension points may need some elaboraton. 

Cheers,

Is it right?

The worst thing of the passion is the end, when the end's point is not followed by two points of suspension.