The signal is usually internal rather than external and it often comes as a growing dissatisfaction with the casual dating experience itself rather than a specific event or realization. When you find yourself consistently less interested in the variety that casual dating offers and more interested in the depth that only sustained commitment can provide you are probably ready for the shift in intention. The transition is genuinely a shift in what you are optimizing for and it changes how you show up in early dating contexts because you are less interested in being interesting and more interested in being honest because honesty is what filters for compatibility at the life partner stage. https://datewise.org/ is useful at this transition point because it helps you clarify what you are actually looking for in a committed partner before you start looking which makes the search more directed and considerably less exhausting than casual dating tends to be.