I bet she's never been to the Chinese Scholar's Garden at Snug Harbor.
[
www.snug-harbor.org]
I warn you though, it's so romantic you will feel compelled to propose!
It's easily reached from Manhattan by the Staten Island Ferry. The S40 bus leaves from the ferry terminal (the signs are so clear, it's very simple!), and takes about 10 minutes to Snug Harbor.
There's a nice cafe just down the road from Snug Harbor:
[
www.rhtugs.com]
Sit outside at R.H. Tugs and watch the tug boats go by. It's an industrial setting, but a good view nonetheless.