australia – rejected Australian tourist visa

My fiance was in Australia with a tourist visa since 3 times since 2016. He always returns to his country before the expiry of his visa. The fourth time he applied, she was rejected on the grounds that they did not think they would stay in Australia temporarily. We are still submitting the same requirements as before but do not understand why his request was rejected. Here is the part of the letter of the Embassy …

The applicant is currently independent and has not provided any evidence of current employment and income commitments. After reviewing the information, I concluded that the Applicant had not demonstrated that he had significant economic ties with the ………… that would cause him to return home during the period of validity of the visa. I have reviewed the offer of support provided by his parent in Australia. However, as a general rule, offers of support or guarantees offered by family and friends in Australia are not sufficient proof of a real temporary stay. It is the responsibility of the applicant to convince the decision maker that he intends to stay only temporarily in Australia.
I am not satisfied that the applicant's personal circumstances support his contention that he intends to remain temporarily in Australia as a visitor. Therefore, I consider that it does not comply with clause 600.211.
Decision
As the applicant is not in compliance with clause 600.211 (c), I do not consider that you meet the criteria for VISITOR visa (FA class) (VISITOR (subclass 600)).
Therefore, I refuse your VISITOR visa application (Class FA) (VISITOR VISITOR (subclass 600)) filed at ……..