Emotions and intent are expressed very differently in Japanese and English. Both in terms of grammar and culture. So direct a translation of 気に入 to "pleased" or "like" is highly inappropriate.
In abstract terms one could say 気に入 means "becoming emotionally attached". Depending on context this can mean positive, neutral and negative emotions.
In the context you give (a girl talking about a boy) it clearly means "I like him".
PS: It frustrated me a lot when I started learning Japanese (and still does once in a while), but you have to unlearn ALL grammar and vocabulary in your mother language related to emotions. Then relearn the very concept of expressing intent and emotions from scratch in Japanese. (At least this holds for a European).
PSS: Once cannot give a complete list of situation in which 気に入 means "like". Usually when refering to a "positive concept" it means "like". When refering to a "negative concept" it may mean "dislike".
PSS: Japanese has a number of words with a contextual "implied negative".
A 外国に行ったことがある？(Did you ever go abroad?)
B 全然 (Never)
A 全然大丈夫 (That's also fine)