sen ‧ ti ‧ ment ‧ al ‧ ize BrE AmE ( also sentimentalise British English ) /ˌsentəˈmentl-aɪz, ˌsentɪˈmentl-aɪz/ verb [intransitive and transitive]
to speak, write, or think about only the good or happy things about something, not the bad things:
novels that sentimentalize the past