Reasoning
Warcraft Tavern's Paladin guide calls Blacksmithing 'an obvious choice' because Paladins use both melee weapons and mail/plate armor, and Forever's new Blacksmithing recipes keep the class geared through leveling. Alchemy is the recommended endgame pairing because Paladins lean heavily on potions, and Forever adds many new buff, damage, and crowd-control consumables (the ACA potion/elixir line). While leveling, the guide advises pairing the crafting profession with its matching gatherer (Mining for Blacksmithing) before switching to two crafting professions at max level. A secondary source corroborates Blacksmithing as the anchor profession but pairs it with Mining rather than Alchemy, so the crafting-profession choice is solid while the exact companion profession is less settled. Source picks: Warcraft Tavern Paladin guide: Blacksmithing (leveling+endgame) + Alchemy (endgame, potion reliance); Koroboost (unverified): Mining + Blacksmithing, secondary Alchemy for raid flasks.
Confidence note
Analysis built from sourced profession facts