We decided to make a branch for some feature so we dont affect the head, now the question is it a good idea to keep merging changes from the trunc in our branch? would this meake the reintegrate easier at the end?
"Good idea" is too weak, it's a must. The longer life of the branch the more important such merges are.
According to SVN recommendations, at least one merge from trunk to branch should happen right before reintegration. In this case reintegration will be automatic, because you've already resolved any problems in your branch.
For short-lived branches this single merge at the end may be sufficient, but if many things happen on the trunk, it makes sense to synchronize more frequently.