A British author has written a book about newspapers and lonely hearts letters, which she says have been a thing since the beginning of newspapers. (Shapely Ankles Preferred, by Fran Beauman, mine is on order from Amazon.) I wondered whether the Pantagraph was ever used for this purpose, but found little evidence for this. I knew that there was an employment agency that doubled as a marriage bureau, but I imagine that Bloomington was too small for anyone to remain anonymous if they wrote a letter or personal ad in the Pantagraph.
What I did find was a smattering of articles regarding people who ran scams through the mail. On March 24, 1915 the Pantagraph reported the arrest of Florence Gamble in Milwaukee for running a marriage scam through the mails. A little investigation revealed that this was the same person who ran a similar game in Bloomington in 1901, named Lizzie Kaburick. Gamble/Kaburick would place ads looking for a sweetheart and accept letters from dozens of men, waiting for her chance to fleece them of their money. Once a victim complained and wrote to the local authorities the game would be up. Elizabeth Kaburick was a student at St. Joseph's Academy in Bloomington in February of 1901 when the US Marshall from Springfield came to arrest her. She had come from Carlinville, according to her. She had worked at a hotel but after the hotel burned down she began going to the school, and, assumably, working this game. She was such a pretty young thing that no one in Bloomington could believe she knew her actions were illegal or that she had conceived of the plan alone.
The closest I saw to a personal ad in the Pantagraph was a mother's ad seeking information about her daughter. Anna B Thompson, of Marceline MO (the boyhood home of Walt Disney BTW), was seeking information about her daughter, Emma Wilhelmina Erickson, who had lived in Bloomington 15 to 20 years before her ad in February of 1916.