I’m using the term Lycanthrope instead of werewolf because she may not have been a real werewolf, but a similar type of creature. She wasn’t a monster of any sort but a decent person with a curse or whatever. I saw it on a late movie in the late 70s.
Not much info here, but I get the feeling it might be “Cat People,” from 1942. Very moody & dramatic, & the lead wasn’t a werewolf, but believed she transformed into a panther. http://www.imdb.com/title/tt0034587/ There were at least two versions; if it was in color it might be the 1982 production. http://www.imdb.com/title/tt0083722/?ref_=nv_sr_1
“Night Tide”(1961)?
http://m.imdb.com/title/tt0055230