Whenever he talks about his childhood, he tends to sentimentalize it, making everything seem perfect.

sentimentalize 是由形容词 sentimental（感伤的、多愁善感的）加上动词后缀 -ize 构成的动词，表示"使变得感伤"或"用感伤的态度对待"。这个词带有贬义色彩，暗示对事物进行不切实际的美化或过度情绪化的描述。