Actually...
Actually, some incidents and legacies tell us that one who thinks well of something, Allah will prove him right and facilitate for him according to his good expectation, as if this is linked to thinking well of Allah. This is so because the meaning of thinking well of someone is rendered to thinking well of Allah Who instilled in him such hidden yet known goodness, that is, the source of everything good is Allah; Allah, therefore, actualizes such a notion, proving its accuracy.
One particular hadith clearly states that if anyone thinks well even of a stone, Allah will place a lot of goodness in it. The person who transmitted this tradition, thereupon, asked the Imam (‘a), ‘... a stone?!’ The Imam (‘a) said, ‘Don’t you see the Black Stone?!’ [^2] One deducts from the above that Allah, Praise and Exaltation are His, proves the good intentions of those who believe in Him with regard to each other, letting such intentions materialize.
Another example is the testimony of those who testify for a deceased person, saying that they did not know anything about him but good things, drawing on thinking well of others, actually on their lack of knowledge of anything bad about him. The hadith states that Allah sanctions their testimony, forgives them and forgives him whatever He knows which they do not know.
The requirement of good intention is that Allah permits it to materialize with regard to the person who thus thinks as well as the subject of the thought except when there is a strong obstacle hindering its application to one who thus thinks of him or of it. In this case, Allah helps its materialization to the other party.
Other legacies indicate that a man may be generous to another man based on his assumption that he is good, so Allah permits him, on its account, to enter Paradise even when Allah knows that the person to whom this man was generous is one of the inmates of the Fire. This is a case when there is a strong obstacle in the way of realizing the good thought about the man who receives such generosity, so the reward is the lot of the other person because of his good intention.
The outcome of all of this is that anyone who acts upon what he is commanded, that is, to think well of his believing brethren, will never be disappointed. His good intention may prove to be accurate, or the matter will be turned according to his own good intention through the mercy of Allah, or He may help such a good intention materialize.