Wa alaikumus salaam warahmatullahi wabarakaatuh Slave of Allah, you have raised a very pertinent issue. One which was addressed only a few months ago in a lecture delivered by Shaykh Riyadh ul Haq at Azhar Academy.
Although some might argue that doubt and suspicion is the reciprocal of misbehaviour and misdemeanour amongst the people, there is no doubt that to re-establish the trust and respect for our fellow muslims is a more positive step to take than to continue to doubt them.
Some time ago, the infiltration of the masjids by people acting as muslims but who were actually undercover 'journalists' was being discussed, and the question arose as to whether this was justifiable reason to be wary of new members of our local masjids. There was no doubt in our minds that it would be better for us to wholeheartedly trust the new members than to doubt them, even if this trust was later proven to be 'misplaced'.
One of the most effective ways of dealing with suspicion, is to remind oneself of the humility of Hazrat Umar when he feared that if he knew only one person was to enter jahannum, that it might be him. When the suspicion of another having committed an ill act enters one's mind, ward it away by recounting one's own countless sins, and fear that they might drag one into the fire.
But this is not enough! We have to CONVINCE ourselves of the innocence of the person. We have committed a crime of the heart when we allow such a suspicion to enter our minds. We must wipe our minds clean of the stain of suspicion by realising the graveness of our error and re-instating the honour of the individual in question.
It is crucial for our spiritual progress that we truly believe ourselves to be the most sinful, and others much more pious than ourselves. Without humility, our souls are lost, since any man who harbours even a grain of pride, will not enter jannah. Surely, if we allow our hearts to accuse our fellow brethren of a crime without any evidence, this is no less than pride and forgetfulness of the Day when WE will be brought to account.
To love and honour our fellow brethren is a MUST. To keep the hearts clean of suspicion against them was the manner of the Prophet and his companions.
May Allah enable us to pursue humility with the fervour of one whose life depends on it! Aameen.
May He forgive us all our shortcomings and enter us all into His Gardens by His infinite mercy. Aameen.