The speaker is warning someone against a shallow kind of love. The subtitle, "open sesame," points to the fairy-tale password that makes a hidden cave swing open. The speaker refuses to be that cave. If the other person thinks love is a matter of finding the right phrase, the right compliment, the right move, then they haven't understood who they're talking to.
The feeling here is guarded but not cold. There's some hurt in it, and a firm kind of self-respect. The speaker wants to be known, not unlocked. The poem's shape helps make the point: the last lines break apart one word at a time, "open / with the / right / words," so the words themselves seem to drip down the page, slow and a little mocking. The mood is quiet, wary and direct, a plain request to be taken seriously as a whole person rather than a puzzle to be solved.