^^^Okay, please don't take offense. I really just want to share my own thoughts to the words I read that are posted on here.
I think in Seiko's dream, her parents' words were her own conscience telling her about HER OWN thoughts. I honestly believe that a person's true thoughts come out in dreams. So while it was through the mouth of her parents, those thoughts were her own. And I think it's very reasonable to say not to the person you love if the life she will have with him will be unhealthy in any way, including physically or mentally.
I don't think that Seiko can be called a tease -- because she was kidnapped and Takeshi decided on his own that he would take her in as his Okusan. She had no say, and if it was a choice between being out in the city battling Aiko's jealousy, or being a bit safer in Takeshi's home, I don't think she has much choice. To me, Seiko has never "led Takeshi on" because all of her words, her actions, have been sincere. And not once has she said or shown that she likes the warrior lifestyle or being Okusan. She openly admits she loves him and she accepts his love, but she has been consistent in reminding Takeshi that their lives are different, she doesn't know how long she can be Okusan. And I think Seiko is a great example of the awesome truth that a woman can be independent; that she can love someone else and also respect herself and her desires; that maybe she is giving him up, not just for his safety, but for herself too.
I understand that this is just a lakorn, and sometimes, I get more attached to some lakorn than to others, so I'm not trying to call anything out.

I just really like Seiko, Takeshi, and I like the circumstances that this love story is set upon. Please ignore this comment if it seems I'm "taking things too seriously" lol because I have a lot of these thoughts when watching Thai lakorn. tl;dr