For a sannyasi , the first qualification should be fearlessness.
Because a sannyasi has to be alone without any support or guarantee of support, he has simply to depend upon the mercy of the Supreme Personality of Godhead.
If he thinks "After leaving my connections who will protect me?", he should not accept the order of renounced life.
One must be fully convinced that Krsna or the Supreme Personality of Godhead, in His localized aspect of Paramatma is always within, that He is seeing everything and that He always knows what one intends to do.
One must have firm conviction that Krsna as Paramatma will take care of a soul surrendered to Him.
"I shall never be alone", one should think.
"Even if I live in the darkest regions of a forest I shall be accompanied by Krsna, and He will give me all protection."
That conviction is called abhayam , without fear.
This state of mind is necessary for a person in the renounced order of life.
Bhagavad-gita As It Is, 16.1 Purport