The Eunuch believed and was baptized . When St. Philip approached his chariot he heard the Eunuch reading Isaiah 53
Isaiah 53:7-8 Revised Standard Version Catholic Edition (RSVCE)
7 He was oppressed, and he was afflicted,
yet he opened not his mouth;
like a lamb that is led to the slaughter,
and like a sheep that before its shearers is dumb,
so he opened not his mouth.
8 By oppression and judgment he was taken away;
and as for his generation, who considered
that he was cut off out of the land of the living,
stricken for the transgression of my people?
Philip asked if he understood what he was reading:
Acts 8:26-40 New Revised Standard Version Catholic Edition (NRSVCE)
Philip and the Ethiopian Eunuch
26 Then an angel of the Lord said to Philip, “Get up and go toward the south to the road that goes down from Jerusalem to Gaza.” (This is a wilderness road.) 27 So he got up and went. Now there was an Ethiopian eunuch, a court official of the Candace, queen of the Ethiopians, in charge of her entire treasury. He had come to Jerusalem to worship 28 and was returning home; seated in his chariot, he was reading the prophet Isaiah. 29 Then the Spirit said to Philip, “Go over to this chariot and join it.” 30 So Philip ran up to it and heard him reading the prophet Isaiah. He asked, “Do you understand what you are reading?” 31 He replied, “How can I, unless someone guides me?” And he invited Philip to get in and sit beside him. 32 Now the passage of the scripture that he was reading was this:
“Like a sheep he was led to the slaughter,
and like a lamb silent before its shearer,
so he does not open his mouth.
33 In his humiliation justice was denied him.
Who can describe his generation?
For his life is taken away from the earth.”
34 The eunuch asked Philip, “About whom, may I ask you, does the prophet say this, about himself or about someone else?” 35 Then Philip began to speak, and starting with this scripture, he proclaimed to him the good news about Jesus. 36 As they were going along the road, they came to some water; and the eunuch said, “Look, here is water! What is to prevent me from being baptized?” 38 He commanded the chariot to stop, and both of them, Philip and the eunuch, went down into the water, and Philip baptized him. 39 When they came up out of the water, the Spirit of the Lord snatched Philip away; the eunuch saw him no more, and went on his way rejoicing. 40 But Philip found himself at Azotus, and as he was passing through the region, he proclaimed the good news to all the towns until he came to Caesarea.
So clearly Philip explained the meaning and "PROCLAIMED TO HIM THE GOOD NEWS". What is that good news? It would be that salvation has come and that salvation is given to those who believe on Jesus Christ. So if Philip explained the meaning of Isaiah 53 then he would proceed to let that Eunuch know what that meant. Therefore, the Eunuch would repent and receive Jesus Christ for the remission of sins, clearly.
