The veteran leader said that despite the sniping over a poor election result and the loss of key ministries in a fresh coalition deal, she felt no decline of her authority and wanted to stay at the helm of Europe's biggest economy until 2021.
"I understand the disappointment," she said, but stressed that she "naturally" planned to stick with her pledge to stay on for four years as chancellor and party chief rather than make way for a successor before the end of the term.
"I am a person who keeps what they have promised," Merkel, who is head of the Christian Democratic Union (CDU), told public broadcaster ZDF.
The 63-year-old won September elections but fell short of a clear majority, in large part due to the rise of the far-right, anti-immigration AfD which took votes away from all major parties.
After a grueling marathon of negotiations, she managed on Wednesday to forge another "grand coalition" deal with the center-left Social Democrats (SPD), who however extracted a high price.
The SPD snatched the powerful finance, foreign and labor ministries as well as the justice and environment portfolios, while Merkel's Bavarian allies the CSU took the interior ministry.
"The transition to the post-Merkel era has begun," judged the Sueddeutsche Zeitung daily, which added that Merkel's power was waning and "a dangerous mood" was starting to spread within her CDU.
Handing over the finance ministry - long the domain of Merkel lieutenant and fiscal hawk Wolfgang Schaeuble - "was one concession too many," fumed lawmaker Wolfgang Bosbach, reflecting a widely held view in the conservative party.
An ambitious rival of Merkel, Jens Spahn, also charged that losing direct control of the public purse strings was a "hard blow" that "hurt" the CDU, speaking to Austrian newspaper Presse am Sonntag.
Spahn, fearing a weakening of Berlin's tough austerity-for-reforms stance for indebted eurozone economies, mused that Greek Prime Minister Alexis Tsipras may now "pop the champaign corks."