If I should find you outside, I would KISS you

[TonyChanYT]

Song of Solomon 8:

1 Oh, that you were like my brother, Who nursed at my mother’s breasts! If I should find you outside, I would kiss you; I would not be despised.

It seems to indicate that she would be despised if she kissed someone, not her brother outside. It should be read from the mindset of the wishful thinking of an innocent girl with no sexual connotation. In contrast, Proverbs 7 describes a brazen woman:

10 Then out came a woman to meet him,
dressed like a prostitute and with crafty intent.
11(She is unruly and defiant,
her feet never stay at home;
12now in the street, now in the squares,
at every corner she lurks.)
13She took hold of him and kissed him
and with a brazen face she said:
14“Today I fulfilled my vows,
and I have food from my fellowship offering at home.
15So I came out to meet you;
I looked for you and have found you!

Does this suggest that it was frowned upon for couples to kiss before marriage?

In the public, I'd say so.