There is a category of highly sensitive people have the gift of empathy. They can easily determine the attitude towards him of another person, assessing his intonation, nonverbal gestures and facial expressions. But if nature has not given you this ability, do not worry because you can develop empathy. Furthermore, communication issues rather useful and intuitive. To date, the Internet has a lot of books, videos and webinars on the development of this amazing quality in which different authors are practicing dissimilar techniques.
Some people turn to astrology, fortune telling and magic in order to clarify the relation of human interests. Thinking about these methods of obtaining information, remember that its accuracy is not guaranteed anything. So it's best to try to learn about their own feelings popular with your personality, not shifting this responsibility on the shoulders of strangers or even close friends.
To learn about the feelings of the person you need as often as possible to communicate with him, but not to impose and do not tire him his society. Over time, you will understand how it applies to you. Typically, the true attitude is known in extreme or unusual situations. Of course, you can directly ask the person about how it applies to you, but it is possible that a truthful answer to this question you will not hear.
Therefore it is necessary to act subtly and wisely, carefully watching the man and his behavior. Pay attention to all his words, deeds, intonation and gestures. Do not lose sight of every detail. Often see in his eyes, because they can see the soul. And, of course, listen to their inner feelings, because the soul, unlike the mind can not be misleading.