He thought that his fast had been spoiled, but he refrained from eating out of respect for the sanctity of the month, then it became clear that it had not been spoiled; does he have to make up that day?

Praise
be to Allah

If a person
believes that his fast has been spoiled, then he refrains from eating out of
respect for the sanctity of the month, then it becomes clear to him that his
fast was not spoiled, then he does not have to make up that day, and the
fact that he believed his fast to have been spoiled does not affect it,
because he did not do anything that cancelled out the fast and he did not
intend to break the fast.

We have
previously explained that the more sound scholarly view is that if someone
becomes uncertain whilst fasting, as to whether he wants to break the fast
or not, then his fast remains valid, and he does not break the fast merely
by thinking (of whether to break the fast of not), so long as he had started
to fast and embarked upon the fast with a firm intention, and has not done
anything to render his fast invalid. That is because the basic principle is
that the fast remains valid, and uncertainty as to whether one wants to
break the fast or not does not undermine the initial intention (niyyah) of
fasting, unless he  firmly resolves to break his fast.

This was stated
in fatwas issued by Shaykh Ibn ‘Uthaymeen and Shaykh Ibn Jibreen (may Allah
have mercy on them both).

See the answer
to question no. 194641

But if this is
the case with regard to one who was uncertain whether to break his fast or
complete it, then it is more appropriate to say that the fast of one who
never thought of breaking the fast in the first place and never did anything
to render his fast invalid – and all that he did was to complete his fast
out of respect for the sanctity of the month – is valid and sound.

Conclusion: this
fast is valid, and it counts as the obligatory fast that he intended to
observe, and he does not have to do anything.

And Allah knows
best.