The Zohar Hakadosh (58B) states: “These are the generations of Noach. He was pleasant (noach) Above and pleasant below."
Sefer Teshuos Chein explains by quoting the Mishnah (Avos 3:10) that says that if one is beloved by people and acts pleasantly with them, Hashem will act pleasantly with him. Thus, the Zohar is saying that the sign that one is beloved by Hashem is if his interactions with people are pleasant.