This verse says that the HolySpirit is Truth. But we know that Jesus is Truth Joh 14:6.
The implication is that the HolySpirit is the Holy SpiritOfChrist Jesus - not another person.
Note also that the HolySpirit is the SpiritOfTruth Joh 14:17. This is another way of saying that the HolySpirit is the SpiritOfChrist Jesus.
This point must be kept in mind as one reads the next verse.
It was impossible for the HolySpirit to speak, and heal and sacrifice and resurrect Himself without a body.
So, the HolySpirit made Himself a body and we call the name of the HolySpirit, Jesus. Jesus is the express image of His HolySpirit.