I'm not sure about the Philippines, but in Canada we often say that men and women think differently about their friends of the opposite gender. Women put the men in their life in either the 'friend' or 'potential lover' category, and it is very rare that they change their mind about a man, and switch him out of the friend category.
Sometimes for men, this can be frustrating, because sometimes a guy doesn't want to be in the 'friend' category. He wants to be her boyfriend, or nothing. And sometimes it can be very difficult for him to get out of that category, as far as the woman's thinking is towards him.
But men think differently. Generally, unless you've been friends for a very very long time, men tend to think of all of their female friends as potential girlfriends/lovers. It's not a better way to think, it's not a worse way to think, it's just men think differently. Consequently, when a woman finds out that one of her male friends thinks of her as a potential lover, it comes as a shock to her. She sometimes feels betrayed, and feels like she can't trust the guy anymore.
But think about this...if he told you the truth about how he feels, isn't that better than him keeping it a secret from you? At least, if he tells you the truth, then it's possible to believe what each other is saying, and maybe a solution can be found.