Thinking it's the motive with と思う
Grammar Explanation: Quoting and reporting with と and って

Makoto and Tsukasa meet to study for an upcoming test. When Makoto spends her study time complaining about it, Tsukasa asks if she hates studying. Makoto says it’s not that she hates it so much as it’s difficult. She asks if Tsukasa likes studying, and he says it’s fun to learn new things and connect them to his everyday life.
- 真:
- 「司
( は頭( いいから」- “That's because you're smart.”
- 司
( : - 「頭
( 良( し悪( しというよりきっかけだと思( うよ」- “I think it's less about whether you're smart or not, and more about having the right motive.”
Key Points
きっかけだと思
( う = “I think it’s the motive”The と marks the content of Tsukasa’s thought: きっかけだ “it’s the motive”.
Because きっかけ is a noun, it needs だ before と思
( う.
What というより is contrasting
頭
( 良( し悪( しというより means “rather than whether someone is smart or not”.Tsukasa is pushing back on Makoto’s 頭
( いいから by saying the deciding factor is not raw smarts.
良
( し悪( し = whether something is good or badHere 頭
( 良( し悪( し means “being smart or not smart”.
Casual ending よ
The final よ presents Tsukasa’s view gently but clearly, as information he wants Makoto to take in.