Kernrechtsfrage
Whether the 12 October 2003 debt acknowledgment bound the appellant for CHF 50,000.
Extrahierter Entscheid
The document constituted a valid debt acknowledgment and the appellant failed to prove that its cause was nonexistent or invalid.
Extrahierte Begründung
The acknowledgment precisely identified the debtor, creditor and amount; under the evidentiary presumption it shifted the burden to the debtor, who did not establish a sham or invalid cause. The Court found the alleged donation scenario implausible and upheld the finding that the respondent's renovation investment plausibly explained the obligation.