import json


def dict_to_json_with_newlines(data):
    """
    Converts a dictionary into a JSON string with explicit newlines (\n) added.

    Args:
        data (dict): The dictionary to convert.

    Returns:
        str: A JSON string with newlines represented as \n.
    """
    # Convert the dictionary to a pretty-printed JSON string
    pretty_json = json.dumps(data, indent=2)

    # Replace actual newlines with escaped newlines (\n)
    json_with_newlines = pretty_json.replace("\n", "\\n")

    # Escape double quotes for embedding inside other JSON
    json_with_newlines = json_with_newlines.replace('"', '\\"')

    return json_with_newlines


# Example dictionary
example_dict = [{"name": "comment_list", "arguments": {"video_id": 456789123, "count": 15}}]

# Convert the dictionary
result = dict_to_json_with_newlines(example_dict)

print("Resulting JSON string:")
print(result)