According to Osho, becoming a sannyasin doesn’t mean accepting loneliness; it means mastering aloneness. Loneliness is a negative craving for others, while aloneness is ecstatic fullness. In aloneness your awareness turns inward, you celebrate your own being, and become so brimful of joy that you naturally relate, love, and share—like a raincloud showering—rather than clinging to others from emptiness.
A sannyasin stops feeling lonely because they enjoy being with themselves and then share that joy with others.