Today's Iwata Asks column for Fire Emblem Awakening detailed the game's love component. This component is part of a greater focus on character to character relationships which tie directly into battle via the game's Dual and Double systems.
Take a look at these systems in action the latest trailer that Nintendo released today. The trailer also shows the marriage component towards the end. In addition to marriage, you'll be able to have kids who can be turned into your allies for battle.