I must be one of the few hoping (in vain, I realize that) that the 'prince' would be Rintaro.
I don't really think Rintaro's been in love with Sakura for ten years. They've been apart for some great period of time before the drama starts, correct? I believe that before that, Sakura was just a close friend, someone to have drinks with. Rintaro has almost specifically stated that he was young, immature and superficial when he was 24...granted, that's a little longer than ten years, but it's close enough. Sakura wasn't even on his radar.
Continuing on, I don't really find the fact that Rintaro likes Sakura as much of a stretch. Hiroto only started dating Sakura not because he was attracted to her but because his sister-in-law asked him to. After he started dating her, he gradually fell for her because of her actions
. These are not
the same antics that Rintaro has previously witnessed. The main reason that Rintaro didn't realize his feelings is because he didn't view her as a woman. The moment the 24-year old came into the picture, that all changed because (a) Sakura's actions were much more feminine and (b) he was going to lose her.
This sparked a change. The actions of Sakura after she started being serenaded by Hiroto are what caused Hiroto to fall in love with her and what deepened Rintaro's feeligns...that's what I believe.
I'm really hoping that Sakura and Rintaro will be endgame...but every single hint points in the opposite direction. :/
1) The actor that plays Hiroto is listed as the second lead followed by Rintaro's actor. (Before I'm called on this being a superfluous reason, I can't recall a single drama where this setup proved false. Tsuki no Koibito and Kekkon Dekinai Otoko to name a couple).
2)The prince of Cinderella puts on the glass slipper. He's wearing white...(up until episode 7 anyways), the only person shown in white is Hiroto.
3) Couples aren't allowed to be 'neat' in jdramas. Tsuki no Koibito, Kekkon Dekinai Otoko, Konkatsu, Sapuri...the list goes on. There's always one-two unrequitted loves. In this case, the sister-in-law and Rintaro. I don't believe it'd work with Hiroto and the sister-in-law because I'm pretty sure Hiroto has some romantic feelings for her (or what could develop into it). While Rintaro will never date the sister-in-law, it's possible that Hiroto might. It's legal in Japan, from what I remember.
None of these reasons are concrete, but they fall in line with the mold of practically every romantic jdrama I've seen. The only one that could possibly
break the mold would be Ninkyo Helper and even that had an ambiguous ending with
I actually dislike Hiroto a lot (I'm definitely one of the few or the only here), so it's disappointing for me. :/ But I love Shinorhara Ryoko, so I'm going to continue to watch, if only for her sake.