William had no girlfriends in high school, and his mother once sat him down at the table in her spotless kitchen and asked if he was gay. She said it would be fine with her. She loved him unconditionally, and they would figure out a way to tell his father. But William wasn’t gay. He was just absurdly, painfully in love with Bridey Taylor, who leaned on the piano and sang while he played, and he had no way of telling her. He was too shy to pursue other girls, even when the payoff seemed either likely or worth the agony. But he didn’t tell his mother that. It was too humiliating. He just stammered an unconvincing denial.
I can not understand what it says in the highlighted part. Could you simplify that? Is there any idiomatic hidden in it?