estaban tranquilizando
Imperfecto progresivo para el sujeto ellos/ellas/ustedes del verbo tranquilizar.

tranquilizar

Era como si ellos supieran algo que yo desconocía y me estaban tranquilizando y animando para que no tuviera miedo.
It was like they knew something that I didn't and they were reassuring me and encouraging me to not be frightened.
Palabra del día
el mantel