Dylan tried. He really did, your honor.
We all saw it. We can all attest that it's not his fault she doesn't know at this point, right??
Did he? The opposite to his verbal attempt here is on paper, as an official document. Do you think any judge would think an undocumented conversation would override a contract willingly signed by both parties? If Duke Dude wants to change things for real, he will need to write a new contract and have Avril read it aloud before agreeing to sign it. That's really trying, not anything we saw in this chapter. All of this is nothing but preparatory work. He needs to spend time with her, keep praising and confessing to her, so that the new contract won't actually come as a surprise. Reading the new contract, she would remember all the times Dylan was confessing his love. Finally, together with the new contract, she would realise it's for real, not just roleplay like her villainess thing.