The German giants have plenty of financial clout, but have no intention of paying over the odds for any of their transfer targets.
BVB has been linked with players such as Kevin De Bruyne, Christian Eriksen and Henrik Mkhitaryan in recent months as it is looking for a replacement for Mario Gotze, but has so far been unable to add a creative midfielder to their squad.
However, Watzke is confident that Dortmund will eventually get the players it wants and has urged the fans to remain patient.
"We are still very ambitious. That means that we have 50m to spend on new players - including Sokratis [Papastathopoulos]," he told Bild.
"Money can solve things pretty quickly in talks with other clubs. However, we do not only have to be ambitious from a sporting point of view, but have to make intelligent decisions financially, too. That's why things are taking a bit longer this summer.
"We will sign two or three attacking players and one of them will be a player for the future. I won't mention any names, though. People shouldn't let rumors on the Internet drive them crazy."
Dortmund has so far only signed defender Sokratis from Werder Bremen for of a fee of around 9.5 million euros.