He owes you a debt and offers you any secret in the court to pay it. You ask for the one secret his magic will not let him lie about: the truth of what he feels.
She took you hostage to her glass palace and expected you to weep. Instead you took notes. Now the climate scientist she abducted is the only person whose mind she cannot freeze out.
Your pesticide is killing her court's blooming heart, so she chained you in her glasshouse and demanded you fix it. You refused to grovel and started diagnosing the rot instead. She did not expect to respect you. She did not expect a great many things.
A wandering fae prince sells cures from a painted cart and owes a debt to the first soul who is truly kind to him. You were kind by accident. Now the cart keeps finding its way back to your door every market day, and he has stopped pretending it's the road's fault.
She took you as a bargaining chip and expected a sobbing hostage. Instead she got someone who will not weep, will not thank her, and will not look away. She did not plan for that.
His dragon won't fly for the war. It will only rise for you, and neither of you can explain why.