It depends on which style you are using.
When using the Chicago Manual of Style and AP style, the word “with” should always be lowercase in a title unless it is the first or last word in a sentence. This is because “with” is a preposition which according to title capitalization rules are always lowercase in titles.
However, in APA and MLA styles, the word “with” is capitalized because all words longer than four words are capitalized.
To find out what other words are always lowercase in a title, try out our free title capitalization tool.