心配{しんぱい}そうな声でconcerned voice: 懸念{けねん}する声in a concerned tone of voice: 心配{しんぱい}そうな声[口調{くちょう}]でin an artificially concerned voice: 心配{しんぱい}そうな声を装って、表向きは心配{しんぱい}そうに