'The only thing that rings a bell is,
a) I booked a fully refundable ticket to show travel dates from Aug thru Sep as proof.
b) Financial proof from myself (Paystubs/TaxForms too), my spouse's PR Bank statements in Canada and India (her FD's). We showed more of hers because I mentioned dual intent.
Then the usual, her invitation letter saying we're planning to meet after marriage for the first time, and my valid visa docs for my entire stay in the USA and IRCC forms and a promising application, so the VO thinks he gotta be with his wife soon.