I've already addressed Mark 16:16. But I will do it again in the hope that you will actually give us your interpretation of the meaning of the words at John 3:16.
"He that believeth and is baptized shall be saved; but he that believeth not shall be damned" (Mk.16:16).
Here the Lord is not saying that a requirement for salvation is baptism with water, but instead He is describing those who will be saved. This is similar to the following words of the Lord:
"And every one that hath forsaken houses, or brethren, or sisters, or father, or mother, or wife, or children, or lands, for my name's sake, shall receive an hundredfold, and shall inherit everlasting life" (Mt.19:29).
Here the Lord says that those who have forsaken their families will receive everlasting life, but surely no one will argue that this is a requirement for salvation. Instead, the Lord is merely describing many who will be saved. Therefore we can understand that at Mark 16:16 the Lord Jesus is merely describing those who will be saved. The words which follow Mark 16:16 demonstrate that the Lord is "describing" those who will be saved:
"And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover" (Mk.16:17-18).
John D. Grassmick writes,
"Though the New Testament writers generally assume that under normal circumstances each believer will be baptized, 16:16 does not mean that baptism is a necessary requirement for personal salvation. The second half of the verse indicates by contrast that one who does not believe the gospel will be condemned by God (implied) in the day of final judgment (cf. 9:43-48). The basis for condemnation is unbelief, not the lack of any ritual observance...Thus the only requirement for personally appropriating God's salvation is faith in Him" (
The Bible Knowledge Commentary; New Testament, 196).
If both "faith" and being "baptized with water" are requirements for salvation then the Lord Jesus would have said:
"He that believeth and is baptized shall be saved; but he that believeth not shall be damned and he that is baptized not shall be damned.".
But that is not what He said.
Now that I have answered your verse twice the least you can do is give us your interpretation of the following verse:
"For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life" (Jn.3:16).
If you fail to give your interpretation for the meaning of these words I will assume you just can't understand them.