here is a riddle can anyone solve it?

[riddler]

what is it.

 

what always is.

 

but is never this

 

for this is to greet

 

as that is to laugh

 

but one comes before

 

the other comes last

[billy the kid]

true Love

what is it. what always is. but is never this for this is to greet as that is to laugh but one comes before the other comes last

[Paulie]

Ok, riddler, what the hell is the answer???