# better than a slave

"more valuable than a slave"

# a beloved brother

"a dear brother" or "a precious brother in Christ"

# much more so to you

"he means even more to you"

# in both the flesh

"both as a man." Paul is referring to Onesimus' being a trustworthy servant. 

# in the Lord

"as a brother in the Lord" or "because he belongs to the Lord"