UPDATE 1-Commerzbank CEO promises quick result in merger talks - memo

Commerzbank's chief executive promised employees on Friday a quick decision on whether to go forward with a merger with Deutsche Bank , according to a memo seen by Reuters.

"I can promise you that we will strive to keep this period of uncertainty as short as possible and we will work hard to ensure that a decision is reached soon," Chief Executive Officer Martin Zielke wrote to employees. Zielke said Commerzbank had a clear idea of how it could develop business in a sensible way. "This is the reason why we are in conversations with Deutsche Bank," he said.

Zielke believes a strong and focused investment bank would be a good fit for Commerzbank, according to a person familiar with Zielke's thinking. (Reporting by Hans Seidenstuecker Writing by Tom Sims Editing by Kathrin Jones and Edmund Blair)