This article analyzes the main contents of the proposed amendments to the Civil Code suggested by the Civil Code Amendment Committee, which was launched on June 16, 2023, in relation to the validity of declarations of intent from a legislative policy and comparative law perspective. First, the proposed amendments maintain the current law for Articles 107, 108, and 110, except for minor modifications in wording. Next, the proposed amendment to Article 109 on mistakes explicitly includes mistakes regarding the juridical act's necessary basis (Grundlagenirrtum) and mistakes induced by the other party as grounds for avoidance. It also modifies the wording of the essential part requirement to clarify the subjective and objective causal relationships as its meaning. Furthermore, it exceptionally allows avoidance even when the declarant is grossly negligent, provided that the other party is also grossly negligent. These changes reflect both case law and comparative law. However, the proposed amendment does not accept the declarant's liability for damages in case of negligence and leaves the possibility of contract modification in case of mutual mistakes to doctrine and case law. Meanwhile, the newly introduced Article 110-2 recognizes a new ground for avoidance when the declarant makes a declaration of intent under undue interference in their decision-making due to a state of psychological dependence or a close relationship of trust. This rule attempts to introduce the common law doctrine of undue influence and protect the autonomy of intent in a manner equivalent to fraud and duress. The content and direction of the above-mentioned amendments appropriately reflect the current state of our doctrine and case law and align with recent legislative trends from a comparative law perspective.