You can use her date scene from the Valentine's Day as a reference to how she'd act. Makoto will act very reserved and polite, and always thinking about others before herself. She wants to depend on her lover, but also not be weak where she can't decide things on her own. You'll usually have to catch her off guard to see her blush, but she can be really cute when that happens.

Voice Reference - https://www.youtube.com/watch?v=400o53Xt_U4