“Soudesune” is quite useful words. Generally, it is translated as “Let me see” in English, but it sounds more polite and sincere. During a conversation, if you are thinking what you speak next, you may say “uh” or ”er”. These don’t sound nice. Thus, instead of them, “let me see” is used in English. That is same as Japanese and “Soudesune” is used.
“Soudesune” means “Yes” or “You are right” originally, but it is also used as a cushion word during conversations. It sounds that you are considering seriously about what your conversation partner said, regardless you are considering that or not actually.
Thus, this phrase is used frequently, especially in business. Mostly, it means not “You are right” but “Let me see”. Somehow, they never misunderstand what the “Soudesune” means in each case.