Whom does God guide to the right pathway? What is the only way to find comfort in hearts?

Verses 27-29 of Chapter 13:

And those who disbelieved say: "Why is not a sign sent down to him from his Lord'' Say: "Verily, Allah sends astray whom He wills and guides unto Himself those who turn to Him in repentance.'' Those who believed and whose hearts find rest in the remembrance of Allah. Verily, in the remembrance of Allah do hearts find rest. Those who believed, and work righteousness, Tuba is for them and a beautiful place of (final) return.