Sharron's birthday gift is Relax Tea Leaves. However, all elemental crystals, excluding Earth, are easier to come by earlier in the game, and raise Love Points and Friend Points just as well. Fire Crystals can be dropped from Kiroris in carmite Cave, in the area where the door shuts behind you, so they are ideal. You will not be able to leave this room until you defeat the monster generator in it. You can't even teleport. Fire Crystals can also be mined easily in... I forget the name, but I think it's Clemens Cave. The one after Tauros Cave.
Every time you give Sharron a Fire Crystal - you must give them one after the other, because a stack of 2-9 will still only register as one - she will either gain a Friend Point OR gain both a Friend Point and a Love Point. So, a guesstimate of about 15 Fire Crystals should be sufficient.
You MUST read the book about THE GRIMOIRE'S SWORD in the library BEFORE defeating the boss of Mt. Gigant, or you WILL NOT get the Grimoire's Scale after your victory! That is urgent! Once you do get the scale, you give to Leo as you would a present - by facing him and pressing "a". He will finish the sword in three days. If it is rainy on the day you can pick it up, you will have to wait 'til the next sunny day, because Leo does not work in bad weather. On a sunny day, when Leo is on the ground floor of his shop, talk to him and choose the fourth option. You get the Grimoire's sword! By now, Sharron should be fully wooed, so give the sword to her and select the marriage option. YOU DO NOT HAVE TO DEFEAT THE BOSS OF, OR EVEN GAIN A PASS TO, THE KASIMIR RUINS!
Hope my novel helps. I know all about Sharron, since she ties with Melody as my favorite.
