The sign of a devotee is transcendental joy. He cannot be judged by the ordinary standards of the secular world.
“The first sign of knowledge is a peaceful nature, and the second is absence of egotism. You have both. There are other indications of a jnani. He shows intense dispassion in the presence of a sadhu, is a lion when at work, for instance when he lectures, and is full of wit before his wife.” (All laugh) “But the nature of the vijnani is quite different, as was the case with Chaitanyadeva. He acts like a child or a madman or an inert thing or a ghoul. While in the mood of a child, he sometimes shows childlike guilelessness, sometimes the frivolity of adolescence, and sometimes, while instructing others, the strength of a young man.” - Gospel of Sri Ramakrishna
According to the Sanskrit devotional classic, Bhagavata Purana, the highest devotee sees God in all beings and all beings in God.
“There are two types of paramahamsas, the jnani and premi. The jnani is self-centered. He feels it is enough to have knowledge for his own sake. The premi, like Sukadeva, after attaining his own realization teaches men. Some eat mangos and wipe off the traces from their mouths.” – Sri Ramakrishna in the Gospel of Sri Ramakrishna

This lecture was given by Swami Tattwamayananda on July 20, 2014.