Okay so I kind of forgot the title of this manga but the story goes like this: the girl is a businesswoman and was forced to work with this guy. At first, she didn't like the guy (4got the reason). So they used the train to go to the place that they need to go. Time skip, the guy kissed the girl while she was sleeping and at the end of the manga the guy told her that he actually kissed her two times. The first time was when they were riding the train together and the girl was sleeping. That's all. Yea I suck at giving descriptions but that's all i could remember. Blame it all to my memory.

Anyways, thanks guys.

The ending sounds a lot like Shuukatsu!! - Kimi ni Naitei . Could that possibly be it?

Yup! That's exactly the manga that I was looking for! Thank you so much! 🙂 )