Every Jewish thinker had issues with Jewish belief. The way that most people understand Rambam – or think they do – he seems like an exception. The credo “I believe with perfect faith” makes Rambam a firm believer in belief.
The problem is that it was not Rambam who said these words; they were attached to his list of thirteen principles – probably centuries afterwards – by a later author. Rambam himself did not speak about belief as much as knowledge.
When Rambam analyses the Aseret HaDibrot, he does not interpret Commandment Number One (“I am the Lord your God”) as “Believe!” but rather as “Know!” His view is that when you know what God has done for Israel and mankind, your knowledge leads to belief – and even if it doesn’t, and you never become a believer, at least you have the knowledge.