public class CreateUserRequest : IValidatableObject
{
    public string Password { get; set; } = string.Empty;
    public string ConfirmPassword { get; set; } = string.Empty;

    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
    {
        if (Password != ConfirmPassword)
        {
            yield return new ValidationResult("Passwords do not match", 
                new[] { nameof(ConfirmPassword) });
        }
    }
}