Marco,
Time here is irrelevant.
'too long' does not affect
interest level DOES affect
The issue here is not on "how long" the time , but "How much" the
person still or has grown to like u at THAT POINT IN TIME.
Ok lets put it this way.
the person can be a stranger, neighbour, friend, classmate,
colleage, acquaintance for the shortest or longest of time.
BUT as long as she/he has romantic interest in u and it stays that
way, then even if its after 10 or 20 years, u r still in the
game.
The only exception is when both parties started off as frds
(meaning to say ZERO romantic interest) and after sometime got
together as a couple. This will only occur, when BOTH parties agree
to bring it to the next level.Whatever the underlying reasons maybe
like loneliness, status, wealth, best frds.
possible as well - but don't count on it