How sound is the Hadith: "He who holds affection for his brother in his heart, yet does not reveal it to him, has betrayed him"?

The Hadith: "Whoever harbors affection for his brother in his heart but does not inform him of it has betrayed him," has a weak chain of transmission (da'if isnad). The authentic Hadith, "If a man loves his brother, let him inform him that he loves him," and his (peace be upon him) saying to a man who loved another, "Have you informed him?" He said, "No." He said, "Inform him," suffice in its place. Al-Khattabi interpreted this as an encouragement for showing affection and fostering harmony, for informing one's brother of love inclines his heart, draws his affection, and makes him receptive to advice.