Checkbox Title

Hello, i use this Code for my acceptance Checkbox. Because i have Problems with the Layout of this.
Now the problem is, that the contact formular can be sent without accepting the checkbox.
How can i change the code? Checkbox must be accepted.

<p style=”font-weight:bold;color:#000000;letter-spacing:0pt;word-spacing:0pt;font-size:13px;text-align:left;line-height:1.5;text-transform:none;text-align: center;”>[checkbox acceptance-715 label_first “Datenschutzbedingungen akzeptieren*”]</p>

Best regards
Stefan