An old-school, straight-faced studio romance featuring five new songs from Ms. Dion, writer-director Jim Strouse’s “Love Again” is all about such healing — to the extent that if it were a book instead of a movie, it would be filed in the self-help section. Liberally adapted from the 2016 German film “Texts for You” (“SMS für Dich”), the more-creepy-than-cute plot focuses on a grieving New York children’s book illustrator who sparks up a relationship with the complete stranger who’s inherited her dead boyfriend’s phone number. “Truly, Madly, Deeply” this isn’t.