Short Answer: "Hey buddy, let's tie the knot!"
Explanation: The joke here plays on the double meaning of "tie the knot." In one sense, it refers to the act of two strings coming together and being tied together. However, it also has a playful reference to the phrase "tying the knot" as a colloquial way of saying getting married. The personification of the strings adds a touch of whimsy to the joke. The use of the emoji adds a cheerful and humorous tone to the answer.
