A woman wants to know if the man that she has interest in is interested in her as well. Through the study of body language and a little bit of knowledge of human emotion, a woman can look at the visible signs that a man shows to see if he shares her feelings.
Body Language 101
According to ChangingMinds.org, one of the quickest ways to tell if any person is attracted to another is to observe his body language. The basic bit of body language that "screams" that one person is attracted to another is the concept of mirroring. If a man is into a woman, he will copy her movements. If she is holding a drink in her hand, he will hold a drink in his hand. If she turns to look at a painting, he will turn to look at that painting with her.
Another basic sign is that a man will face his torso toward the woman he is interested in if she is in the room. Even if he is talking to another person, his head may be facing that person, but his torso will face the object of his affection.
A man who is in love will keep the promises he makes. If he says he will call, he will call. If he says he wants to take a woman out that weekend, he will take that woman out that weekend. If he breaks promises on a regular basis, there is something wrong. If he respects a woman, he will follow up on what he says and treat her with the same respect he offers his friends.
A man who is in love with a woman will introduce her to his friends. He will want his friends to like her and work hard to make sure that she is happy in their presence. Additionally, he will want to introduce her to his family. If he is "hiding" the woman, he does not love her.
A player will quickly throw out the phrase "I love you" and will make sweeping, over-the-top promises quickly and then disappear when he has got what he wanted. A man who is love will wait to fulfil his physical desires, out of respect. He will think and plan his declarations of love, including saying those three little words.
Another more subtle move of a man who is interested in or in love with a woman, according to a BBC article on relationships by Tracey Cox, is the "eyebrow flash." It is hard to detect, but as soon as a man notices the object of his affection, he will move his eyebrows up and down quickly to denote excitement at the presence of the woman. Additionally, a man (or woman) in love will have dilated pupils. These two signs of love are difficult to catch, but impossible to fake. If a man is showing either of these signs, he is definitely in love.