Mrs. Martin didn't genuinely want Isabelle and Jeffrey Foster to be together; her daughter's self-pitying, timid demeanor simply triggered her competitive spirit.
She felt she had spent half her life raising a beautiful and charming daughter, so how come she couldn't catch an older man? Especially one who was blind!
No matter what, she had to have her daughter rope him in first, and then she could break up the lovely couple at her leisure!
Otherwise, how aggrieved would her daughter be?
Isabelle didn't know her mother's true intentions; she was overjoyed to hear her mother relent, and she threw herself into her mother's arms.
Meanwhile, Mr. Martin looked suspiciously at his wife; hadn't she been strongly opposed just a moment ago? How come he disagreed, yet she suddenly aligned with their daughter?