If you do not like sending plain letter like an unattractive bond paper and white envelope only, you can go for having stationery paper instead. Using stationery makes your receiver feel more appreciated by you. Much more if you will make it more customized and personalized.
There are lots of stationery paper designs found on the internet which are already printable as well as their envelopes. But the thing is you can go beyond the designs that are available on the internet. You can put some personal stuffs like a picture of your loved one, a button to close the flap of the envelopes you are using or put some shells or might as well paint it they way you want to.

You can choose soft colors if you want a sweet effect on the paper, or dark and artistic colors that may reflect your personality or the receiver’s character. The more personalized it is, the more it becomes more attractive and appealing to the eyes. Nothing beats the fact that you express your emotions, in cases of a love letter to a loved one, in a presentable manner. The one receiving it would have second thoughts of throwing it.