The Chinese character for "love" or "to love" is 愛 ( ài)in traditional Chinese, but it can also be written as 爱 ( ài) in simplified Chinese. Traditional Chinese is more commonly used in Taiwan and Hong Kong, whereas simplified Chinese is used in mainland China.
The main difference between the two characters is that the simplified version does not have the component, 心. In Chinese, 心 (xīn) means "heart." Thus, a running joke among advocates of traditional Chinese is that there is no "love" in places that use simplified Chinese because the character is stripped of its heart. (but editor doesn't agree with the point...)
愛 / 爱 can be used as a noun or as a verb—to love someone or to love doing something. The character is roughly used in the same manner as the Chinese character 喜欢 (xǐ huan), which means "like" or "to like."
The pinyin for 爱 is "ài." The character is pronounced in the 4th tone, and can also be referred to as ai4.