What books would you recommend to a suicidal person, for example, to give them a reason to hope? Or a reason to trust, have faith, love, not despair? Something to orient myself towards God?

Tolstoy’s Confession. There is a link to the full text if you’re interested. Only 80 or so pages. Not exactly the monumental tome that something like War and Peace is.

It is precisely about what you’re dealing with, stemming from Tolstoy’s own years long suicidal ideation. His eventual solution? Belief in God. If you prefer something with a drastically different conclusion, perhaps I would suggest Camus.

My money is on Tolstoy though, and most specifically on God.