In general

  1. Status update of your love interest with no valid reasons.
  2. Seeing your ex with their new toy, happy and giggling.
  3. Seeing your new crush interested in a newer entity.
  4. Seeing your fan type lover not giving you much importance.
  5. Your crush describing you plans of her Valentine’s day celebration with her lover.
  6. Mind games from whom you once loved.
  7. Friendly ‘hi’ from your lover turned ‘very good friend’.
  8. Last minute cancellation of Valentine’s day date on pretext of ‘I am busy’, while you guess ‘where and with whom?’.
  9. Heart saying yes but ‘ego’ saying no.

https://hemantpandeyblog.com/2017/12/30/how-can-we-be-sure-that-we-really-love-someone/