Deanna is such a sweet, old fashioned woman, she was about 23 in "Because of him". Deanna was 13 in her first appearance with Judy Garland in the short "Every Sunday" 1936, and that came out 10 years prior to "Because I know him" 1946. Deanna blossomed into a beautiful young woman in her 1940s films such as this one. And her voice is wonderful again here singing her lovely opera songs especially the tear-jerker "Danny boy".
The golden age had some beautiful operatic singing women, Janette McDonald in the 1930s and early 1940s, and Kathryn Grayson and Deanna Durban in the 1940s. All angels
Deanna had a deep admiration for John and wanted to star in his show so badly that she folded a letter that she typed herself about being invited to star in John's show, and asked him for his autograph with him only seeing the side of the paper without the letter showing. Since Deanna was waitressing and John was a customer at the restaurant she waitressed at, she was able to pull it off with John not discovering until later what she'd done. John did take it better than many characters of his sort in these types of films would take it. Generally, he took it well enough to remain calm and sympathetic towards Deanna and to keep her scheming move quiet and between only the two of them. But he didn't take it well enough to actually grant her wish to star in his show, and bluntly advised her to go back to her home town. Then Deanna, well at least her friends and family, did not keep the next plot point quiet. They publicised in the newspaper that she attempted suicide due to John's rejecting her for his show.
John's reaction to that, like with the autograph/letter scheme, was lighter than one would've expected, and he then really developed a soft spot for her innocence and determination. After that came Deanna's beautiful "Danny boy", and Deanna and John were not the only ones without dry eyes. I have a sentimental side to Golden age music, it's simply got a sweetness and charm to it that no modern music can match. Deanna Durban, Kathryn Grayson, Janette McDonald, Judy Garland, Nelson Eddie, Allen Jones, Dick Powell's singing, Ginger Rogers, Jean Harlow, Ruby Keeler, Clark Gable, Gene Kelly, Cary Grant's acting and charm, along with many others' singing, acting, sweetness, and charm have all helped to have made the pre-mid-1950s age a wonderful place