Question

I am sure of His Success make it Complex

Answer 1

I am sure that he will succeed

Answer 2

The sentence in the question is in simple sentence.

A simple sentence is a form of sentence which has one independent clause and has no dependent clauses. It can stand alone for its meaning as a sentence.

Whereas, complex sentence refers to the sentence which contains at least one dependent clause and an independent clause. A dependent clause is the clause which cannot stand alone in its meaning on the other hand independent clause refers to the phrase which can stand alone, though both have a subject and a verb.  

Therefore, when the sentence is converted into complex sentence, it would be written as:

I am sure that he will succeed.

Herein, 'I am sure' is the independent clause and 'that he will succeed' is the dependent clause.