This is a man who is intent on making you never regret deciding to get into a relationship with him.
In telling you that he wants to give you his all when you two get into a relationship, he wants to reassure you.
He knows that going from being a friend of yours to a boyfriend is a giant step.
He is fully aware of this.
To this end, he doesn’t want you to have any doubts about getting into a romantic relationship with him.