Twinkle
http://www.mangago.zone/read-manga/twinkle/
Yaoi manga that really sweet and fluffy!
http://www.mangago.zone/read-manga/kimi_ni_yoseru_blue/
The art is so clean, the story is so innocent and pure (⁄ ⁄·⁄ω⁄·⁄ ⁄)
Interesting question. Hmm...see, My personal definition of Pure love is very VERY different from others. So the ones I am gonna mention might not be your cup of tea.
1. Itou-san (Kurara Sui) : If this is not pure love I don't know what it is. IMHO, this is by far THE MOST pure love manga among ALL the ones I have read in my entire life.
http://www.mangago.zone/read-manga/itou_san_kuraka_sui/
2. Wish (CLAMP) : You'll understand why it's about PURE LOVE when you read the last chapter. It's just too heart wrenching,too beautiful & too good to spoil.
http://www.mangago.zone/read-manga/wish/
3. Replay (Ryu Riang) : Re-incarnation theme but do NOT make the mistake of assuming it as your typical re-incarnation manga. This will break your heart & prove your assumptions wrong at every possible twists & turns!
http://www.mangago.zone/read-manga/replay/
4. ZE (Shimizu Yuki) : Not recommending it because it's my Top Fav but because it's a Rich collection of Different types of Pure Love. They'll seem superficial at first but you'll see how very Pure their love is from the way they develop.
http://www.mangago.zone/read-manga/ze/
5. Boys Next Door (Yuki) : An extremely tragic twisted yet somehow peaceful manga. You can't help but love the characters & pray for their happiness.
http://www.mangago.zone/read-manga/boys_next_door/
6. Chobits (CLAMP) : Clamp is Mastermind when it comes to portraying Purest forms of love. Especially their old works. This one too will seem silly & typical at first but turns into those big jaw dropper at the end.
http://www.mangago.zone/read-manga/chobits/
any pure love manga? the purest love