Is Lee Rang's romance really a force one or not?

I think it's not that rush. I didn't see Rang opened up that much for the mermaid yet, though it's subtle but still not yet. 

Rang will need this romance. It's to help him understand what love means and to make him understand more of Yeon's actions and love for him. He will finally know that Yeon never abandoned him. If Rang can figure it out, then Yeon will have no problem going back because by then, Rang will have a life of his own where he'll be happy with his life and love.  Yeon will be happy if he sees his baby brother living happily, even after he's gone. 

No, it is not forced and it is a subplot anyway. I also agree that Lee Rang needed romance in his life. Look how unexperienced and obtuse he is when the girl is giving him hints that she is interested in him. But he is slowly open up to another person. He is really a softy but he is so guarded. I laughed when he was so happy when he found out that the baby Mi Ho ( Fortune God)  liked him better than Shin Joo. He did not wanted to say goodbye initially and it was obvious that he liked her.

I see his romance storyline as a character development.

To me, the character of the mermaid is quite bland tbh. However Rang's oblivion and innocence is quite fun to witness.  At least  for now. 

I don’t have big problems whit Rang’s romance line. First of all, if I see a good looking  guy, I would attract to him.   Second, both of them half-blood creatures,  and the mermaid mentioned she has problem to fit in, because she doesn’t belong to either world. So, she would attract to him more. Third, to me it is kind of refreshing when the woman fell first, and the male lead miss the obvious. It is always the opposite. Most of the time I have no clue why the  male leads fell in love in the first place. Seriously, it seems like they never seen a woman before in their whole life. Anyway, I admit it is not a deepest and most perfect relationship I have ever seen, but at least it is not the main plot and has some cute elements.

Be serious. Who wouldn't fall in love at first sight with one of the Lee Brothers in their suits back in a time where everyone was poor? lol. Especially when you really want to fall in love like Yeo Hee. Girl was determined to have her romance plotline! So if  you say it's forced, yeah maybe it wasn't "organic" like she tripped and he caught her as far as kdrama tropes go. In fact, I love that she's been the one that's been saving him and that's how he falls for her...instead of those silly tips she gets from the magazines lol. For me who has watched S1 twice, I want Rang to have some romance in his life. As a Kim Bum fan, I'm here for the potential loveline angst! 

 MysteryBehindAll:

At first, I was pretty apprehensive of the romance between them. But I must say I've warmed up to them. I think Lee Rang can now have a life outside of his brother. Don't get me wrong, I love the bromance between Lee Rang and Lee Yeon. But it's rather sweet and funny to watch Lee Rang, someone so guarded, slowly opening up to someone and falling in love. It's nice to see him get a life of his own. It doesn't feel forced to me.
What am I scared of is that the mermaid will die in the end or something.  I cannot watch the pain on Lee Rang's face if that happened.

Don't say that the mermaid will die man. I don't think I can handle seeing Rang cried again. His brother's death taunted him so much. Even though he hasn't experienced his brother's death yet, her death will be just as impactful as Lee Yeon's, since she's his lover and his new family now, aside from Lee Yeon.

 Taenak:

Don't say that the mermaid will die man. I don't think I can handle seeing Rang cried again. His brother's death taunted him so much. Even though he hasn't experienced his brother's death yet, her death will be just as impactful as Lee Yeon's, since she's his lover and his new family now, aside from Lee Yeon.

I wish I could say otherwise. But I've got a feeling she just might die. I truly hope she won't though. I too wish not to see Lee Rang in pain. Well.. let's see what happens

 He Lian:

Not really, but I feel that Mermaid is going to die before the drama ends. That's why she didn't appear in S1 and Lee Rang never accepted Na Ri's romantic advances in S1. 

Oh no....... T^T