Thank you for submitting your item for appraisal. This appears to be a ca. 1939 Longines white gold diamond bezel wrist watch, having 12 round cut diamonds at the hours, second dial at six o'clock . Few similar watches were sold in the past several years ago, therefore the value might be a little higher, considering the possibility the metal band might also be white gold. This has to be checked hands on. Gold hallmarks might be very small and hard to detect.
There is no measurement for the sentimental value you might attach to the watch.