Plum Bay beach would be the closest. We have villa Truffle mapped out on the bottom of the page.
http://stmartinblue.com/villa/truffle-st-martin
It's less than a 10 minute walk (750m) but you have to account for the uphill walk on the return.
To be more specific, here is the distance mapped up from the villa to Plum Bay beach.
https://goo.gl/maps/DQp9kukraQn

It's a gorgeous villa. It will have much better views than Bamboo but a similar standard of design level. While Bamboo has a slight Asian characteristic, Truffle is a bit more neutral on the contemporary scheme. It's a very popular trend these days. Open formats, clean lines and aesthetics with big views.

Rob