Tei Taion Danshi ni Natsukaremashita.

"My smile is specially reserved for you." Kotori Ogata, self-conscious about her plump figure, is inexplicably adored by Soma, a younger coworker known for his frosty demeanor. The reason likely traces back to a rainy day encounter: Kotori finds Soma shivering at a bus stop and, being a meddlesome caretaker, helps him warm up. Since then, Soma has been incredibly affectionate toward Kotori. He defends her from sarcastic comments from her manager, holds her hand claiming he's cold, and even sweetly tells her, "Everything you do is adorable to me." Step into this romance and experience the cute moments between warm-hearted Kotori and her frosty younger coworker, Soma!
(Source: MangaPlaza)