Board Thread:Nintendo 3DS/@comment-131.216.14.1-20130312204822/@comment-3448772-20130312212235

You can get Chrom to marry Olivia by having him have a higher support rank with her than all of his other marrige canidates. The easiest way to do that is to not have Chrom stand next to those other units and having him pair up with Olivia when she joins your team, until they get married.