Key legal question
Whether X. was bound as a solidary co-debtor for the loan
Extracted holding
Yes. The contractual documents and X.'s signed declaration showed that the parties intended him to be a solidary co-debtor; simulation and contrary explanations were rejected.
Extracted reasoning
The cantonal court established the parties' true common intent, or at least an objective meaning under the trust principle, from the clear wording and circumstances. In a reform appeal, that factual assessment was binding.