someone who is sentimental is easily affected by emotions such as love, sympathy, sadness etc, often in a way that seems silly to other people:
She said a sentimental goodbye.
People can be very sentimental about animals.
based on or relating to your feelings rather than on practical reasons:
He wasn't the sort of person who kept things for sentimental reasons.
a sentimental journey to the place of his birth
The rings that were stolen were of great sentimental value (=important because of your feelings or memories relating to them).
a story, film, book etc that is sentimental deals with emotions such as love and sadness, sometimes in a way that seems silly and insincere:
a sentimental story set in Russia