Four Seasons Fleur Dress is crafted with Tailoring in Mabinogi (clothes). This page lists everything needed to make it, checked against the game as it exists today. The interactive planner lives in the Tailoring Companion.
How to get the sewing pattern
The sewing pattern is rank 1 and survives 30 uses; every crafting attempt spends one use.
Fleur (Monster) (10 Uses): Defeat Fleur in the Forest of Four Seasons in Mag Mell on Hard difficulty.. Requires the Mag Mell Hard difficulty fight to see the pattern drop.
Materials
Expect about 10 attempts per finished item (10% average progress per attempt). Per-attempt materials are consumed on every attempt; finishing materials once per item.
Each attempt uses
4× Scented Silk — Gathered in the Forest of Four Seasons fairy area.
4× Fragrant Petal — Obtained from the Forest of Four Seasons reward chest.
5× Thin Thread Ball — Hot-Air Ballooning reward (6-10 stars) or gift from Simon
Finishing (once per item)
2× Fragrant Finishing Thread — Drops from Fionnait in the Forest of Four Seasons.
2× Wisteria Decoration — Progress through Fleur's Mag Mell missions for a chance to receive it.
1× Magical Grain — Chance reward from the Mag Mell mission reward box.