Does amateur Recital must pay deflect cost if I target an enemy unit with deflect?

Yes, you must pay the Deflect cost if you choose to target an enemy unit with Deflect using the ability of Amateur Recital.

Reasoning:

• Targeting: Although the text of Amateur Recital says "you may move a unit," the game rules interpret abilities that require you to select a specific unit as a target as "choosing" that unit.
• Deflect Application: According to Rule 809.1.c, the Deflect keyword is functionally short for: "Spells and abilities an opponent controls that choose me cost an amount of Power equal to [Deflect Value] more to play as an additional cost for each time they choose me."
• Mandatory Cost: Per Rule 356.2.a.2, the cost imposed by Deflect is a Mandatory Additional Cost. You must pay this cost during the process of finalizing the ability on the chain. If you cannot or do not pay the Deflect cost, you cannot choose that unit as a target.

This is consistent with RiftJudge FAQ #8505, which clarifies that abilities requiring selection of a target incur the Deflect cost, even if the word "choose" does not appear in the card text.