Are you a believer?

The meaning of 'belief' according to the early Muslim sages:

"... with regard to the answer, 'I am a believer if God wills', [in response to a] question put to one: 'Are you a believer?' The reply should not be 'I am a true believer' or 'I am a believer [in] God'.

These qualifications are correct [and] put forward for four reasons, [the first] two [] do not come from doubt and [the second] two come from doubt.
(1) Care taken for fear of showing oneself pure... A certain wise man was asked, 'What is detestable talk?' He said, 'To praise oneself'.
(2) Courtesy and to entrust all actions to the will of God...
(3) ... There is doubt whether [one] is a perfect believer because God said, 'True believers are those only who believe in God and His Apostle and afterwards do not doubt and who fight with their lives and properties for the cause of God. These are the truthful'...
(4) The fear of [a] bad end, for no one knows what will be his end, good or bad."

(Source: Imam Ghazzali's Ihya-Ulum-Id-Deen)

Am I a believer? Yes... insha-Allah!

Note that there is difference in meaning between the words Mu'min (roughly: a believer or one who confirms the truth - from the word Eeman) and Muslim (roughly: one who submits, surrenders and avoids unbelief, rebellion and disobedience - from the word Islam).