Or indeed anyone buying chocolates for anyone on any occasion, it is likely that your recipient will be thrilled anyway but with a little research you can get it just right. The main point here is know who you are buying for.
Strapped for cash: A present does not mean expense, when the gentleman of the house and I were poor students he would occasionally surprise me with a gift of chocolate buttons and I thought it terribly romantic. Later when he had a little more cash started getting me Green & Blacks bars (image source)
Her absolute favourite: If you know his/her absolute favourite chocolates then you may be on to a win (however make sure its something they actually do like, not something you buy every year and they are too polite to say anything) (image source)
The Chocolate Connoisseur: Did you know you can now buy single estate chocolate bars (image source)
Its all in the presentation: If you want to make a real splash (and have a pretty box to use later) I saw these in the Leonidas window and couldn’t stop going ooooh (image source)
Alternatively there are these much cheaper tiny truffle boxes from Charbonnel & Walker (they’re so adorable and yum too) (image source)
Dairy Free, Glutan Free, Vegan: There is even chocolate available for those with specific dietary requirements. Booja Booja truffles are all these and they also sell raw organic cacao beans! Im definitely curious to try those (image source)
Alternatively why not treat yourself to your favourite chocolates this valentines day, at least you will always know what you like (yum yum yum)