“Shabbos Chazon, Tishah b’Av, Shabbos Nachamu… A Shabbos of solemnity…before Tisha b’Av, followed by a day of intense mourning…on Tisha b’Av itself, and bookended by a Shabbos of comfort and consolation.

…

How can we call the Shabbos after Tisha b’Av, ‘The Shabbos of Comfort’…?

Our Sages…teach that…after a year has passed following [the death of a loved one] the pain and agony of the loss dissipates. Hashem, in His Kindness, ingrained such a phenomenon into our psyche, for He knew that holding onto the loss for too long would overwhelm us.

But what does it mean if, even after a year and certainly beyond the distress and anguish is still there?

…

The Torah relates that Yaakov Avinu refused to be comforted after being told that his son Yosef had been torn apart by a wild animal… One can only attain consolation at some point for someone who dies, but not for someone who is alive. [He] remained inconsolable…because Yosef was, in fact, alive.

…

The Chassm Sofer [explains that] the very fact that we still remember the Beis Hamikdash to this day and cry and mourn its loss indicates that it is still alive in our hearts and minds… [It] is not eternally destroyed, [not] forgotten…

Shabbos Nachamu is thus a time of comfort for we know with certainty that the rebuilding of Yerushalayim and the Beis Hamikdash is a reality very close to our hearts and fully alive.”